When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Trying to make more power than the power adder is designed to do by over spinning it is going to drop eff. like a rock and raise charge temps. So trying to up the engines top end eff. and make it breath more with a blower that's already huffing is backwards math.
If trying to get the most bang for your buck. Boost is the most efficient at making power, period. A larger blower making its rated boost/rpm VS an over spun blower will have lower IAT's at the higher boost pressures you need. Looking at the site, in general... F1x is rated to 1300-1400ish. The F194A is 1050-1150ish (CRANK HP). Not much in-between for bolt on units.
So get the big boy blower first. You don't need some fancy high flow top end or a ton of cubes for your goal. You simply need more boost.
A more cost effective setup would be a simple 6.0 9:1 motor (or less). Keeping the cubes relatively small and dropping base compression down so a 4 bolt head stays sealed at big boost. Ideally you'd want to pulley the blower to max speed, then drop base compression down until your power goal was met. That will give you the most reliability and easiest to seal combustion chamber at that power level.
Going this method you could make your goal on ANY of factory untouched head by simply adding boost until your power goal was met. If you (like many) insist on higher base compression levels, then go with a more cost effective thick deck head. Something like the $1200 TFS 225's is all that's needed.
I think 243 will be fine. Over the years I went from 241 to 243 and 317 heads all around the 700-800 WHP point. I'm sure there were some minor power differences, but nothing that stood out. I ended up with the 317 head to help bring the compression down and ran them all the way up to ~850 WHP and they seemed to work fine.
On a budget, I don't think there is anything wrong running the 243 head. I run pump gas so lower compression is important, but if you are running E85 or a heavy methanol spray then I think 243's will be fine.
The only issue I ever had with the stock castings is that they became easy to lift approaching the 900 WHP point. An engine or so ago I went to an aftermarket with a thicker deck and 1/2" head studs because I got tired of fiddling with head weeping if everything wasn't perfect and coolant getting under the tire isn't awesome.
I know the forum wizards will claim their heads never lift (ie. the rest of us are morons), but I think stock castings become hard to hold down as you go over 1000 flywheel - but you can make it work.
Save the money and leave the 94 on it for your goal, the F1x is just going to be more hassle trying to A) Fit it in a GTO and B) Try to make belts live, you'll need 10-rib minimum if trying to keep your GTO bracket and I still will bet on belt dust.
While I suggested the BR1's and MAST 295's in your other thread, the above TFS245's are definitely a proven cylinder head, I'd be seeing what the selling price is on those.
To the original ask, as most have said, they'll work but you'll end up most likely right where you are now however with a better bottom end and oiling if going aftermarket block. There are things you could do to the 243's for better sealing and possibly push the envelope but why risk it until the budget allows.
You seem to like to argue and must always be right.
Modern Prochargers can make way more than advertised and do not drop of spinning them a few thousand rpm over the recommended max impeller speed.
I think you had a Procharger many years ago and do not realize how much they progressed in the last 5 years.
Yes I could put a bigger blower on it now but the ls3 block would be pushed beyond its limits.
you missed that part because you don’t listen and only want to be right in every argument.
Assuming I missed something or that I care if you think what I say is accurate is cute, but incorrect. What I said is simple fact. If you can't get your head around it, it makes no difference to me.
You seem to want to make things overly complicated that aren't. As well as spending money where its not needed. Then make points that have nothing to do with the topic. You get upset about blower VS turbo nonsense and can't focus on anything else.
I discussed the rated power levels the manufacturer uses for your chosen power adder. Even put s little *ish* next to it because I knew you'd comment on it. Yes, we all know it can squeak out more. Same with most power adders. The fact is you are pushing the blower you have as is. A larger motor with a better top end is not the smart path to more power. I agree with beefing up the block. You're $4000 head comment made little sense if you are on a budget and have "x" goal to meet on that budget.
I simply stated the facts to get the most power out of the least amount of money for the power adder you chose.
I've seen that video when it first came out and I've seen others make over 1200 rwhp with the F1a-94 as well.
While I agree with your overall message there are a couple points I'd like to make...
I'm not as good as LME. I will be assembling the long block and doing all the tuning myself. While I'm confident in my abilities I'm not LME and do not have a team behind me it's just me.
I will be running an air to air intercooler not air to water. I want the car to be daily driver friendly. I do not drive it daily, but when I do want to drive it I like to just check fluids quick, fire it up, and go. I want daily driver reliability.
I will be running pump E85 not C85 race fuel. I like spending barely over $2 a gallon on E85 out of the pump 5 minutes from my house. Not sure how much C85 gains, but they wouldn't use it if it didn't gain anything over pump E85.
I do not feel for a second my rods/piston ls3 is going to last long with 1200+ rwhp and while I accept risks of the hobby, I'm not into just blowing things up ***** nilly either. I would like a more reliable bottom end as I do drive the car to and from the track as well.
Several good points have been made and I'm taking everything in to consider everything as I have plenty of time to make decisions.
So back to the original question with a twist. So, if I already have ported 243's that only need a spring kit installed and maybe new valves (if you think I should replace the stock valves with stainless or inconel) you think I'm safe to 1200 rwhp on 4 bolt stock casting heads? If so I currently use ls9 head gaskets and arp head studs, but if I go to a 4.125 bore what gaskets should I use? Am I fine with 4 bolt stock casting heads without top fuel hoops or even mini hoops? Just the proper gaskets and heads studs would be fine at 1200 rwhp?
My close friend had problems blowing head gaskets over 1200 with an oem iron block and lsa heads on e85 so it makes me leary.
I don't recall a turbo ever being mentioned not sure why you are bent out of shape that I'm using a procharger?
You said throw the bigger blower on it now and I stated I don't feel that my current short block will hold up to 1200 rwhp.
I obviously understand how adding boost is the cheapest way to make more power as I'm making around 1000 rwhp with unported 241's currently.
Alot of people make 1200+ rwhp with an F1a-94 which is more than procharger says they make at the crank, but like I stated I want to make the power easily and not have a maxed out combo.
I have zero IAT problems over spinning the blower currently even with the restrictive top end. Prochargers do not have an IAT problem even when being over spun with an air to air intercooler.
If you don't care what I think of your opinions, then why continue to post in my threads? My comment about your liking to argue isn't based upon any thread we've talked in but an overall judgement of EVERY thread you post in regardless of the topic. You seem to like to argue and will not accept any other way except your way.
The original question was... is there an argument AGAINST using 243 heads on this combo with my plan/goals in mind? You are literally arguing in favor of my original question that is why it seems like you just like to argue and can't ever be wrong.
LOL... we always have honest discussions about car parts and prices before I purchase. She loves racing and loves that I have a hobby like this so as long as bills are paid, we have cash to get by for a year without income, and I'm contributing a generous amount to the 401k she's fine with it.
Current power ratings for procharger street head units... With procharger rating the F1a-94 at 1300 and knowing full well they rate the max impeller speed conservatively I do think with a strong bottom end and a more efficient top end I can hit my 1200 rwhp goal with the F1a-94 that I currently have. If not the new F1r-103 coming out is supposed to make F1x power in an F1a-94 size head unit so that would be an option as well.
LOL... we always have honest discussions about car parts and prices before I purchase. She loves racing and loves that I have a hobby like this so as long as bills are paid, we have cash to get by for a year without income, and I'm contributing a generous amount to the 401k she's fine with it.
Thats awesome to be in a situation like that, goals for sure lol
is there any reason I should absolutely not use ported 243 heads with stock valves on a 388” lsx block if I already have them ?
The reason I ask is simply for budget reasons while wanting a stronger bottom end than my current ls3 with forged rods and pistons.
I plan to go with a forged bottom end lsx 4.125 bore and 3.622 stoke, Johnson lifters, btr 660 springs in the heads, my current ws6store max effort rockers.
The plan would be to put better heads on it later 6 bolts thicker decks and push the power later.
Personally I would not spend the time/money switching to a 243 head on your current motor, nor would I put 243s on a built motor later and would run something better. I would probably sell the 243s and keep that money to put towards something else.
Originally Posted by BCNUL8R
Current power ratings for procharger street head units... With procharger rating the F1a-94 at 1300 and knowing full well they rate the max impeller speed conservatively I do think with a strong bottom end and a more efficient top end I can hit my 1200 rwhp goal with the F1a-94 that I currently have. If not the new F1r-103 coming out is supposed to make F1x power in an F1a-94 size head unit so that would be an option as well.
Keep in mind that the GTO bracket will absolutely not handle a larger blower than what you currently have without flexing and shredding belts. I'm honestly surprised it's holding up so far with the F1A-94 and would bet money that if you were to pulley it any more aggressively it would start being an issue. You can literally push on the blower/bracket and watch it flex and years ago we developed a support bracket to try to stiffen it up and it helped a little bit, enough to run the next size pulley down but nothing more than that.
Personally I would not spend the time/money switching to a 243 head on your current motor, nor would I put 243s on a built motor later and would run something better. I would probably sell the 243s and keep that money to put towards something else.
Keep in mind that the GTO bracket will absolutely not handle a larger blower than what you currently have without flexing and shredding belts. I'm honestly surprised it's holding up so far with the F1A-94 and would bet money that if you were to pulley it any more aggressively it would start being an issue. You can literally push on the blower/bracket and watch it flex and years ago we developed a support bracket to try to stiffen it up and it helped a little bit, enough to run the next size pulley down but nothing more than that.
Im not putting a dime more money into the current motor as it’s already being pushed to its limits imo.
I bought the 243’s dirt cheap they just need new springs and maybe a valve job or a sloppy lap job. So you’re saying don’t run the 243’s under any circumstances on the new motor?
I’m currently spinning the f1a-94 to 80,000 rpm with no issues. 8.25 crank pulley 4.0 blower pulley shifting at 7200 rpm. I fabricated my own brace and it works well only an 8 rib setup. I run the standard gates belts even just use the shortest one I can stretch on it. Been working well for the last couple years at this boost level. No significant belt dust and boost climbs all the way to the shift point.
I may try the new f1r -103 same size and step up of the f1a-94 but claimed to make more power than the f1x.
Im confident the Procharger combo can get me to the 1200 plus range but I will wait until I can get better aftermarket heads if you recommend against the 243’s at that power level.
Im probably over 1000 rwhp now but haven’t dynoed to know for sure. I’ve been a best of 5.9x in the 1/8th at 3800 lbs and you are aware that is pretty damn good for a nearly full weight GTO. Not sure what you ever ran in your GTO when you owned one. I went 10.2 in the 1/4 with mine back in 2006 408 with nitrous combo back then. That one was tuned by Jim at speed. I sold it in 2008 and bought this one around 7 years ago. I’ve done all the work and tuning on this one.
I bought the 243’s dirt cheap they just need new springs and maybe a valve job or a sloppy lap job. So you’re saying don’t run the 243’s under any circumstances on the new motor?
I personally would upgrade to an aftermarket casting of some sorts.
Originally Posted by BCNUL8R
I’m currently spinning the f1a-94 to 80,000 rpm with no issues. 8.25 crank pulley 4.0 blower pulley shifting at 7200 rpm. I fabricated my own brace and it works well only an 8 rib setup. I run the standard gates belts even just use the shortest one I can stretch on it. Been working well for the last couple years at this boost level. No significant belt dust and boost climbs all the way to the shift point.
Well that's good, just seen way too many of these old bracket setups just bend and destroy belts but it sounds like the added brace is certainly helping.
Originally Posted by BCNUL8R
I may try the new f1r -103 same size and step up of the f1a-94 but claimed to make more power than the f1x.
If it truly does make more power than an F1X I would at least expect it to have the same type of load on the belt as an F1X which is a LOT more than what you currently have with the F1A-94. When I ran the F1X on my C6 it was very touchy with belts, and that was with a pretty decent bracket setup too. I was running a 4.25 pulley with an 8.00 crank and it was spinning to 8200 rpms so that's around 83,000 blower speed. LOL
Originally Posted by BCNUL8R
Im probably over 1000 rwhp now but haven’t dynoed to know for sure. I’ve been a best of 5.9x in the 1/8th at 3800 lbs and you are aware that is pretty damn good for a nearly full weight GTO. Not sure what you ever ran in your GTO when you owned one. I went 10.2 in the 1/4 with mine back in 2006 408 with nitrous combo back then. That one was tuned by Jim at speed. I sold it in 2008 and bought this one around 7 years ago. I’ve done all the work and tuning on this one.
It was right around 4200 lbs raceweight, plenty heavy with the 4L80, turbos, etc. Ran a best of a 10.12 at like 138 mph after I had made a small cam change but never ran it with the transbrake to actually build boost at the line nor did I ever put a drag wheel/tire setup on it. I think it was only cutting 1.7-1.8 60's at best without the brake. The turbos were tiny little 2871r and it only made around 780 rwhp or so to run that number at that weight.
I personally would upgrade to an aftermarket casting of some sorts.
Well that's good, just seen way too many of these old bracket setups just bend and destroy belts but it sounds like the added brace is certainly helping.
If it truly does make more power than an F1X I would at least expect it to have the same type of load on the belt as an F1X which is a LOT more than what you currently have with the F1A-94. When I ran the F1X on my C6 it was very touchy with belts, and that was with a pretty decent bracket setup too. I was running a 4.25 pulley with an 8.00 crank and it was spinning to 8200 rpms so that's around 83,000 blower speed. LOL
It was right around 4200 lbs raceweight, plenty heavy with the 4L80, turbos, etc. Ran a best of a 10.12 at like 138 mph after I had made a small cam change but never ran it with the transbrake to actually build boost at the line nor did I ever put a drag wheel/tire setup on it. I think it was only cutting 1.7-1.8 60's at best without the brake. The turbos were tiny little 2871r and it only made around 780 rwhp or so to run that number at that weight.
I was leaving off idle in the first GTO and this one as well. My 60' times with the first one were in the 1.5x range with a 3600 stall and drag radials. I daily drove that car because it was the only car I owned back then. Only made 480 rwhp on motor and 632 on 150 shot, but we didn't have the heads and intake options back then. Cams and tuning has advanced since then as well. Current car I use stiff wall slicks on and plan to use Hoosier QTP's for street car nights that require DOT tires.
I'm not in a hurry to build a new combo since my current one is still performing well so I can take more time to gather parts and go with aftermarket casting heads.
So my next question for you is:
Are 4 bolt heads good enough for 1200 rwhp and definitely will not be over 1300 rwhp? If so what head gaskets or tricks do I need besides good head studs?
What block do you recommend for 1200 rwhp? I want it reliable at that power level assuming no fuel delivery issues, tuning issues, or other problems to cause detonation obviously. I also don't want to spend money unnecessarily to buy a 2000 hp rated short block either. The aftermarket blocks are mostly all 6 bolts but if putting 4 bolt aftermarket casting heads on it would be sufficient, I would go that route as the high quality 6 bolt heads get really pricey. I don't really trust TSP castings and they seem to be the only budget 6 bolt heads I'm aware of.
Cam will be custom most likely another cam motion, johnson link bar lifters, and keep my same ws6store "max effort" rockers if possible. I also would keep my BTR cathedral port equalizer intake.
Are 4 bolt heads good enough for 1200 rwhp and definitely will not be over 1300 rwhp? If so what head gaskets or tricks do I need besides good head studs?
What block do you recommend for 1200 rwhp? I want it reliable at that power level assuming no fuel delivery issues, tuning issues, or other problems to cause detonation obviously. I also don't want to spend money unnecessarily to buy a 2000 hp rated short block either. The aftermarket blocks are mostly all 6 bolts but if putting 4 bolt aftermarket casting heads on it would be sufficient, I would go that route as the high quality 6 bolt heads get really pricey. I don't really trust TSP castings and they seem to be the only budget 6 bolt heads I'm aware of.
In that car with that weight, not in my opinion. If you had a 2600 lb shitbox you could probably get away with it for a short while. But if you listen to the internet you can make 2000 horsepower on a stock 4.8L engine and have it live for 100 years in an 18 wheeler so...
I really like the LSR blocks from Concept Performance, keep it aluminum and keep weight out of that thing as it's heavy enough.
One thing I would highly consider is a good A2W setup, the Procharger intercooler is not great on the GTOs and there are big gains to be had just by switching to an A2W Garrett core as it's MUCH more efficient. In fact, I would do that before doing anything else. On the C7 and Gen6 Camaro Procharger kits we have seen a 140 horsepower increase just going from their A2A to our custom Garrett core A2W setup on a highly spun setup.
In that car with that weight, not in my opinion. If you had a 2600 lb shitbox you could probably get away with it for a short while. But if you listen to the internet you can make 2000 horsepower on a stock 4.8L engine and have it live for 100 years in an 18 wheeler so...
I really like the LSR blocks from Concept Performance, keep it aluminum and keep weight out of that thing as it's heavy enough.
One thing I would highly consider is a good A2W setup, the Procharger intercooler is not great on the GTOs and there are big gains to be had just by switching to an A2W Garrett core as it's MUCH more efficient. In fact, I would do that before doing anything else. On the C7 and Gen6 Camaro Procharger kits we have seen a 140 horsepower increase just going from their A2A to our custom Garrett core A2W setup on a highly spun setup.
LSR blocks with with stock GTO oil pan? Otherwise, I think they have a cover kit for them and everything else works with stock accessories, starter location, etc. right?
If your dead set on 1200whp I feel you will have issues keeping it sealed. If you just switch directly to the forged motor you will probably make slightly less peak and a few rpms earlier. You can cam the hell out of it to help crutch the heads. I would at least start with arp2000 studs or better. Keep timing soft unless you get better heads later on. I’m sure you know 1200whp is 1400 plus flywheel plus driving the head unit.
In that car with that weight, not in my opinion. If you had a 2600 lb shitbox you could probably get away with it for a short while. But if you listen to the internet you can make 2000 horsepower on a stock 4.8L engine and have it live for 100 years in an 18 wheeler so...
I really like the LSR blocks from Concept Performance, keep it aluminum and keep weight out of that thing as it's heavy enough.
One thing I would highly consider is a good A2W setup, the Procharger intercooler is not great on the GTOs and there are big gains to be had just by switching to an A2W Garrett core as it's MUCH more efficient. In fact, I would do that before doing anything else. On the C7 and Gen6 Camaro Procharger kits we have seen a 140 horsepower increase just going from their A2A to our custom Garrett core A2W setup on a highly spun setup.
Thanks for the care and effort you put into writing that statement. Very much appreciated.
If your dead set on 1200whp I feel you will have issues keeping it sealed. If you just switch directly to the forged motor you will probably make slightly less peak and a few rpms earlier. You can cam the hell out of it to help crutch the heads. I would at least start with arp2000 studs or better. Keep timing soft unless you get better heads later on. I’m sure you know 1200whp is 1400 plus flywheel plus driving the head unit.
I have a forged rods/pistons motor now, but stock crank and stock ls3 block with stock 241 heads. I don't think I would lose anything going to a larger cubic inch fully forged bottom end with better heads with the same blower/impeller speed. I would just make the same or slightly more power at a lower boost pressure correct?
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.
