A little background on the car. i bought her about 8 years ago not running, have been replacing stock parts just to keep her running until now.

after dealing with major electrical issues, burned out optisparks and emission system issues just to start with, its been decided its time for me to build her from the ground up. engine is lt1 350

options 1, keeping her a stock 350 block, forged rods and crankshaft from callies, custom pistons to raise compression to 11.5:1, afr lt4 195cc, 65cc chambers titanium retainers, 700+ max lift valve springs, lt4 intake fully ported to match heads, 52 or 58 mm throttle body, 36 or 44 lb injectors, all msd ignition, custom camshaft, crower shaft mount rockers, pacesetter long tubes, 2.5 inch dual exhaust, everything else built around those specs. hp goal of 450 to 475 to the wheels

option 2, 383 stroker, forged rods and crankshaft from callies, custom pistons for 11.5:1 compression, afr lt4 210cc, 65cc chambers or afr lt4 227cc, 65 cc chamber, titanium retainers, 700 or so max lift valve springs, lt4 intake fully ported to match heads, 52 or 58 mm throttle body, 36 or 44 lb injectors, all msd ignition, custom camshaft, crower shaft mount rockers, pacesetter long tubes, 2.5 inch dual exhaust, everything else built around those specs. hp goal 550 to 575 with 500 to the wheels.

side note, i know i will need to do a full suspension, transmission, rear end, drive line, and brakes upgrades, but for now im just trying to figure out my engine setup and build all of that around it. i am also open to different brand names on any parts.

my questions, can i achieve my hp goals with either of these setups? what type of piston do i use? and what should the specs of the piston be to achieve that compression ratio? aftermarket ecu? anything im forgetting?

any advice is greatly appreciated, i know there is a ton of knowledge on this forum. thank you in advance

 

A4 or M6?

Assuming we're talking about a car w/manual trans, 450-475rwhp out of a 355 would have to be solid roller setup but it's definitely doable. The biggest problem with this setup is the stock PCM isn't going to take you farther than 7k (or 7.2k w/OBD2) so plan on upgrading to 24x. The engine is going to have to rev higher than what the stock computer can handle to make the power you want. You can get away with reusing the stock crank but I would at least stud the 2-bolt mains and get a line hone for peace of mind. Add in 6" rods and pistons (both must be reasonably light) and you'd be set.

The 383 is going to take much more $$$.

Why 65cc chambers? 65ccs is too big for a NA 355. The thinnest LT1 specific gasket you can get off the shelf is the Victor Reinz one at .026". To get your desired compression you'd have to do a good bit of milling and decking which will only create problems when you go to bolt your intake on and bring your valves closer to your pistons. You also need adequate quench distance for your motor to survive so getting to 11.5 will be a challenge. The only other way to bump comp up is with domed pistons but that's opening up a can of worms (possible fitment issues and less efficient/slower burn). Getting 11.5:1 on a 383 is a little more doable but I still think the chamber is too big for a NA app. Stick to a chamber around 55-60cc and run flat tops or d-shaped dish if needed.

Get a general idea of what kind of power or ET you want and build the car back to front. Rear, driveshaft, and trans to hold the power but don't forget suspension and tires. You want useable power. When that doesn't translate to speed it's like blue *****.

 

You seem pretty ignorant about how to go about this stuff.
The first sentence of option 1 shouts that loud and clear.
Settle down and gain a whole lot of understanding before you go any further.
If that offends you maybe stop and consider my signature, been there done that, made plenty of mistakes myself. Your plan is one of someone without any experience.

Why would you buy a forged crank to stay stock stroke unless going lite weight and even then a stroker crank is no more cash just an extra $100 clearancing. Deliberately looking at 65cc heads for a NA 350 is another statement of pure ignorance.

The blind faith in AFR and LT4 says your research consisted of reading magazines.
You are aiming grossly oversized on injectors.

Your plans are great for a magazine article but a joke to most of us who have built quick LT1s.

And 11.5 is very low for a built LT1 NA

 

+1

11.5 really should be the least you want... High compression lt1's are in the high 13.5:1 range. What are your plans for the vehicle??

 

65cc chambers?

You should go with a nice S480 turbo.

 

450 is doable for a 7K limit 355. It's easier if going over 7K, but not necessary. However, you really need to know what you are doing. A 383 will NOT automatically add 100rwhp. Maybe 30, not even 50. Assuming CID/power density, my build would increase about 32 hp. But, not all things will be equal. My intake manifold and TB are already too small and would show more restriction with more displacement (I drop about 6-7kPa at WOT vs Baro as I sit, I should be 1-2kPa difference). My cam would drop it's power band down and HP = TQ at RPMs. So those need to be considered.

450rwhp 355 will not happen with 65cc heads though. The 11.5:1 CR pistons would be rated (if for an LT1) with the stock heads/specs. With the 65cc heads, you're looking at 10:1. That's in a decent boost range for an LT1 (stock is 10.4:1 and people boost that routinely).

DO NOT replace the stock crank for a forged piece, unless your crank is broken (even then I'd go with another stock crank) or you are going with a longer stroke. Pure waste of money if not for a stroker.

I'm going to assume that emissions legal is not a concern. If that's the case, then keep the CC's down. Mill the heads to flat and you should be in the 54 to 52cc range. You want high compression, 11.5:1 isn't all that high for an LT1. If you go big with the cam (with 450rwhp goals you'll need too), you can get more aggressive with the SCR to great advantage too. Basically, a big cam + high compression = a larger tq curve.

"11.5:1 pistons" means about as much as "3/4 race cam". What we need are actual specs of the piston. Compression height, rod length, ring size, dish/dome cc's, etc. I'd recommend flat top forged 4340 pistons with 4 valve reliefs (~-7cc), 6" rods and a compression height to match, thinner rings, on 52 to 54 cc heads. Have the block decked to zero with those pistons and rods, and a .030" head gasket. That'll put you between 11.8 and 12.1 SCR for a 355, you could probably go higher. 12.6 - 12.9 for a 383, I'd shoot for a .035" head gasket here to get to a 12.4 - 12.7 SCR on a 383, but I'm a little more conservative than others.

Learn what quench is and apply it.

Try to find a cam with....... Better yet call Lloyd or AI and they'll spec one for you. Let them know if you'll be on the stock PCM as that'll be a limiting effect, if you plan on keeping the stock PCM that is.

Be careful going with anything other than stock (with the exception of the MSD Opti) for an Opti based ignition system. In fact, just don't. Unless you go completely away from the Optispark system, keep it as stock as possible. Wires and Cap and Rotor are o.k to improve aftermarket.

Your injectors are good for E85. If sticking with pump gas, 30-36# are good. I'd lean to 36#, they cost the same (sometimes cheaper, less demand) and have room to grow.

You're exhaust looks like a good plan, but duals are hard to deal with, fitment and ground clearance are a real issue with our F-Bodies. A Single 3.5" or 4" would be a better bet, although not as "cool".

The real questions though, from us, are:

Budget? Goals? Emissions? Track only? DD?

 

You don't need custom pistons for 11.5:1, just smaller chambers and off the shelf pistons.

 

@96capricemgr, no offense taken, but i wouldnt say ignorant more like inexperienced. this is my first build so I do expect harsh "don't do this or your wrong here, here and here with your idea's" replies, however basically calling me stupid isnt exactly constructive to me learning from you or others experience and advice when you instantly put me on the defensive. i came to this forum so i could get advice from you guys who have been building these cars longer than i've been alive most likely. to clarify a couple things, i dont care if the parts come from afr, ai, trick flow, or whoever makes the parts that will work for what i want. the only reason i was going with lt4 intake is because i wasn't aware of a readily available option that bolts to lt4 heads.

@Catmaigne, A4 car at the moment, doesnt have to stay that way but it would be preferable since driving the streets of seattle washington in winter with a 6 speed doesnt sound like a fun idea. after reading the first few replies im dropping the first idea and going with a 383 build, drop the combustion chamber cc's to 55-60 based on what advice i get from you and others.

I would like to keep my budget at $8k-$12k on the engine, this is somewhat of a long term project as i will be buying parts for this over about the next year.

goals, dd car, 383 stroker, 550 rwhp, n/a, preferably staying a4 or going aftermarket auto due to winter conditions here. car will probably see the track during the late spring summer months, would like to see low 11's high 10's. I wouldnt mind getting rid of the opti so 24x conversion? or?

 

ig·no·rant
ˈiɡnərənt/
adjective

lacking knowledge, information, or awareness about something in particular.

stu·pid
ˈst(y)o͞opəd/
adjective

lacking intelligence or common sense.

He called you ignorant, not stupid. Lacking experience, by your explanation IS ignorance. This forum is full of very technical people. (LS1Tech), a bunch are just ******** with holier than though attitudes, but most are literal and technical. Calling you ignorant, from 96CapriceMgr isn't offensive (notice he called him self that when refering to where you are at when he was) it's a fact that you admitted to.

No need to get offended by the truth. Too often people use that word completely wrong. He called you ignorant, not stupid.

$8-12K is a decent budget. But, it depends on who's doing the work. Are you doing it all yourself? If so then it's doable. 550rwhp NA is a tall order though, maybe look at a 396 at that point, and yes a 24x.

 

Over 500rwhp pretty much never happens on pump gas in an LT1, especially in an A4. I can think of 1 motor that made 700 flywheel on 11.5:1 compression, with VERY ported and expensive hogged out 227s. 450, doable, 475, maybe, 500, not for $8-12 grand. Either go LS, or turbo.

 

DD and solid roller aren't really two things you want to mix. You can build a hydraulic roller 383 that will make 450-475rwhp on pump gas and it will be much more street friendly. Not cheap.

 

@96capricemgr, i apologize, my fustration with this car bled over into my repsonse to your message, and also led me to take it the wrong way.

@hrcslam thank you for clarifying, now that i have my fustration work out i realize your very right and i took things the wrong way. there are a lot of very intelligent and technical people on this forum as i have found over the years of reading that has helped solve numerous issues i have had with my car.

after reading the responses it seems like my goals are going to be very hard to reach if i stay n/a, however catmaigne what would be the combo you had in mind for making 475 rwhp n/a?

now if i did go with forced induction, supercharger or turbo? aiming for the higher end what kind of hp numbers can be expected for either combo reliably?

 

How much power do you have experience with?
500 rwhp is 10s in a halfassed setup car much less a well setup one.
400rwhp is plenty at near legal speeds on street tires.

 

You are going to dd 500rwhp in severe winters? You need to gopro that.

 

Your goals are doable, just not ALL of them at once.

You can have your 500rwhp with a solid roller AFR headed 383, but it won't be a DD and you would be lucky to do it for $8-10k. Will need lots of RPM, lots of cam, and lots of money. My "temporarily abandoned" build was being spec'd for 500rwhp through an auto and there is half of your budget just in the top end and valvetrain. Not counting rotating assembly, block, fuel system, computer and electrical, transmission, rear end, TB, etc.

Your Option 1 is a lot more feasible, but would need some changes...the shaft mounts won't be necessary, so you can save a few hundred there. The cam will need to be an HR if you want a true DD, but to make 450rwhp through a 355 it will need to be fairly large. Aftermarket castings usually still need some finishing by hand to be "perfect" for a build and it probably wouldn't be worth it on Option 1, so again you will save some more money going with well ported stockers. That money saved between the heads and shaftmounts can go to a 24x setup for ease of tuning.

With your budget and experience I would ignore forced induction for now. Build a nice stout 425-450 rwhp 355 and then see if you really want more.

TL;DR: Option 1, a stout ~425-450rwhp 355, but change a few things to better spend your money and reach your goals.

 

Hmm... with everything I have read about the OP. I believe that the OP should do a simple turbo build on the 355. Take slow steps and find someone to help you that doesn't charge an arm or a leg. The goals can be easily met and be very DD friendly. Keep the stock heads and go to a custom turbo grind. A nice set of forged pistons. 24x and a 4l80e should help. 8-12k should do it if most work is done by OP. Only a few things need to be outsourced in this particular situation.

Of course a LQ9 could be swapped and cammed to make 450 rwhp and be much less $$$.

 

This. Or even a 5.3L turbo build....

 

Give me about $8000 and i'll send a 383ci LT1 stroker motor to your house that will make enough power to make your neighbor three houses down **** himself while he's sleeping when you start it.....

Lunati crank, oliver rods, JE pistons, AFR 227's, solid roller, single plane, 83 lb/hr injected beast of a motor......

went 10.60@128 naturally and 9.0@154 in a 3400 lb tank....

gonna hafta be quick tho bc ppl are salivating about buying the heads/manifold/tb separately.....

then i'll only have the shortblock. which is STILL a serious ******* piece of LT1 hardware.... for that i'm going to need about 5 grand....

 

after seeing the replies on here, an engine swap is sounding much more viable option, although that would need to be postoned untill i have the chunk of cash to just do it all at once since i need the car driving.

however the car is on its last legs as it sits now, as far as i know near 300k on original injectors and valvetrain she just does not want to keep running. so let me ask a new question, if i do a rebuild, H beam rods, new pistons, rings and have the rotating assembly balanced, a camshaft kit and new injectors and a tune. if i use this camshaft kit http://www.summitracing.com/parts/cca-k07-464-8, what would need to be done with the heads and intake to have it run right. is that cam kit even a viable option?

 

Gonna come off as a dick but if you picked that cam package you need to stop everything and ******* READ. Read, read, read, find a build you like, and copy that. You have a LONG way to go before you should open your wallet. That cam is for a TBI 305, not an lt1 350. It's too small to notice anything over stock.