all im sayin is I make about 425rwhp with a dana S60 rear and stock shortblock with a mild HR cam and they are STOCK ported heads by Lloyd Elliot! I dont see my numbers being that shy of the link you posted at the FW

 

Alot can be done with factory castings, but AFR is the best LT head out there.

 

True....... but not out of the box,
Your looking at least double the price to get the extra power out of them.
You need to buy these, then have them ported to be worth while over a stock ported head.
There are guys running 10s NA on stock heads. Unless your going ALL OUT aftermarket heads are not worth it IMO, and I just went trough all this. My results speak for themselves
Aftermarket guys can send me their heads and I will test them myself on the dyno and track to prove otherwise.

 

Tony, you should know that I'm an AFR supporter and have purchased 2 new sets of my own, not to mention recommending them to friends. The original poster was looking at buying used small-port AFR heads, which is why I posted the flow numbers and recommendation against buying them.

One question, though - I noticed in the dyno test that the 383 still needed 37 deg of timing to get max power. Why hasn't the chamber been updated to a fast-burn design requiring <30 deg?

 

There are other advantages to running aftermarket heads.

1. You are getting BRAND NEW castings, zero heat cycles. There is a small chance you take when you ship your stock heads off that they will be deemed junk. Not saying it happens often, but i'm sure every porter has seen cracks and stresses beyond repair.
2. They are thicker in critical areas. Usually in the deck area. The TFS heads specify this in their description.
3. They can be opened up for more airflow beyond what a stock casting can do. I know this will be a touchy area, since the stock LT1 castings have been shown to make more power than most will ever need. But look at the ported TFS heads, or AFR 210's 227's, RR 215's, Dart's, etc.. Eventually you MAY look to upgrade beyond what a factory ported head can do. The last I checked, a COMP ported AFR 227, and the older RR 215 had some flow numbers out of the box that are simply untouchable from a factory ported head. Not starting a war here, just saying what i've seen.
4. Not sure where you come up with "double the price". I honestly don't know what you paid for your heads, but I was quoted sub-$1870 (assembled)for an aftermarket head that flows over 300cfm at .500",and keeps progressing above .600" (ie; doesn't stall). I find it very hard to believe that your ported stockers hit 300cfm, or that they only cost $925---assembled. What heads did you get? I'm assuming LE2's or LE3's, and they are $1350/$1600. I just checked his site and they flow "about 275/190 (2's)and 280/195 (3's)". Those are great number for sure, but in a year or 2 you may get bored with what you have...then what? Those will be pretty much maxed out, not much more you can do with them.

 

Are those times in your sig with a set of afrs joelster? If so what ones? Thanks

 

Let say someone had no desire to upgrade later on. For the extra $520, how much more hp and tq are you going to get on a 350ci LT1 over the ported LE's, all else being equal spinning to 6200 or so rpm?

 

Im curious if you have you ever tested an AFR Eliminator out of the box??

IMO, we offer the biggest bang for the buck in an out of the box head capable of big power without investing another penny. Need more air, then step into our Comp ported Eliminator for even more airflow and additional power potential. At that point I would out our product against any "one off piece" out there that costs even remotely close to the same money. Guys hanging their hats on spending loads of money on ported stock castings are also barking up the wrong tree....they need material added in the right places (almost as much as removed) to design a really efficient port....few porters are welding and/or adding epoxy and if they are your paying an arm and a leg for the work and are left with compromised welded/epoxied castings when the smoke clears anyway.

Once again, look at what the new Eliminators offer and look at the finished (ported) volume they offer that airflow at. Ported stock heads need alot more volume to come close to the peak numbers (and will usually fall short in the low/mid lifts) and wont fill the cylinders nearly as effectively. Average airflow is higher with our clean sheet design as is airspeed which better packs the cylinder and reduces overlap issues for much stronger low/midrange grunt as well. Part throttle isnt even a contest....the smaller, more efficient AFR head will make your engine feel like you just picked up 40 CID with the gains in SOTP low speed torque (ideal for a street/strip car that actually sees a fair amount of time on the street).

Check this thread if you have time....

http://forums.corvetteforum.com/c4-t...der-heads.html


No problem....may have taken your post slightly the wrong way.

Regarding timing its certainly compression and combination sensitive (I think that engine had low CR). Most of the better working Elim combo's seem to like around 34-35 degrees. Keep in mind we are still filling a cylinder with alot more air and fuel than a stock head and are still dealing with a 23' valve angle, not a modern much flatter valve angle head (our LS Gen III stuff usually likes around 28' of lead for max power). I say give the engine what it wants....if you can still run close to 11 to 1 CR on pump gas with zero detonation issues (and make big power), I dont care what the timing light says to be perfectly honest.

I believe this GM Vortec head is a fast burn design....look at the huge disparity in power between it and a 195 street Eliminator, not our higher flowing Comp ported design.
(scroll down a bit after this page loads)

http://www.airflowresearch.com/195vsvortec.php

The new AFR heads are the real deal guys....do your homework and speak with people truly in the know. Barring that google AFR Eliminators and see the host of good news that search will likely bring from people out there actually using and experiencing the product.

Thanks,
Tony

 

No, those times are with a mildly cleaned up TFS 195cc head, which dropped my compression down to around 9-1. My combo is hardly optimized, big cam, mid-level heads, low compression, but we made it run some decent numbers.

*New combo in the works though*

 

Was that the aluminum 200cc large port fastburn heads, or was it the iron vortec heads?

 

Tony I wanted to thank you for the help and I will try to call and discuss more of what I want out of my setup.

 

I believe it was the large port aluminum version....Hot Rod magazine did the test as part of a huge camswap test they were involved in. They were curious about the effects of good heads on a camswap as well as the results from the just the cam swapping themselves. They swapped five different cams in both combinations (Vortec and AFR heads).....no other changes.

I will try and verify with Marlin Davis who did the actual testing.

No problem....my direct line is 661-705-8508

Thanks,
Tony

 

just for comparison - i spoke to dave layer at heads up cylinder heads (well known in the nhra super stock classes) about porting a set of heads. he gets $1500 for a hand port and valve job, and $4000 for his cnc ported stock casting. there is extensive filling and welding and epoxy in this head. it maintains the stock port volume and flow a little less than an off the shelf afr. lets talk about bang for the buck cnc lt heads. granted his heads are class legal and have gone mid-9's na in a fully prepped class car, how streetable are they?
i would personally run the afr before i spent nearly the same money for less power from a stock casting. there is something about having new casting with a deck surface nearly double the thickness of stock. that is a small detail that tends to be important in most fi combos.

 

I did a little digging and I compared some info here that I thought might be of interest to a lot of people. This info is taken directly off of the AI website and the AFR website.

Here is a comparison between the AI stock ported 200cc versus an AFR 195 "street" and an AFR 195 "comp" head. Take special note of the price too > You have to factor in an additional $50 or so to have your stock heads shipped out to AI for porting.



Lift:..........AI 200cc Int.........AFR 195 St Int..........AFR 195 Comp Int
.200"............147.7......................137... .......................140
.300"............204.6......................196... .......................202
.400"............247.4......................243... .......................248
.500"............275.1......................274... .......................280
.600"............287.8............................ .........................300
price*......$1975+core+shipping.........$1769................$2449
..................*cam included!!***

ex.
.200"............115.9.......................110.. ........................115
.300"............153.0.......................158.. .........................165
.400"............178.8.......................190.. .........................200
.500"............190.2.......................207.. .........................217
.600"............196.2.......................211 (.550").................225

They are pretty close in the intake side with the AI 200cc slightly edging the "street" version of the AFR 195 but not the "comp" version. But the exhaust side is no comparison at all. I got the prices for the AFR's directly from an AFR authorized dealer. I simply googled an AFR part number and clicked the very first link that I saw.

Now here's AI's top dog! Their 215cc ported Trickflow casting! Let's see how it stacks up against an AFR 210cc "street" and "comp" head.


lift..............AI TFS 215cc..............AFR 210 Street................AFR 210 Comp
.200".................146.2....................... ...139................................147
.300".................206......................... ...199.................................206
.400".................253.3....................... ...249................................257
.500".................284.9....................... ...279................................290
.600".................300.4....................... ...295................................308

ex
lift
.200".................110.6....................... ...110................................120
.300".................148.6....................... ...158................................166
.400".................176.9....................... ...192................................214
.500".................195.9....................... ...210................................225
.600".................204.8....................... ...214................................235

price.................$2495....................... ...$1999............................$2574

Again, very similar to the first comparison, with a close group on the intake and a huge margin on the exhaust side. Make note that I am comparing a smaller AFR port here too

Now I'm gonna let you guys in on a little secret here.............None of the AFR dealers disclose their lowest prices, ever. What I mean is, they CAN sell you stuff cheaper, you simply have to ask them. It never hurts to ask. I just ordered a set of 227's for a song, I simply sent out a few emails to a few AFR dealers. The 227's require a few special parts (stud girdle) or shaft rockers (street use), but they flow ENORMOUS amounts of air. No ported stock head can touch them, it's not even close. I got the "street" version and I put a little comparison up including the price to the AI 215 TFS head.

lift...............AI TFS 215...........AFR 227 "street"
.200"................146.2...................... 148
.300".................206........................ 210
.400"................253.3...................... 259
.500"................284.9...................... 292
.600"................300.4...................... 305

lift ex.
.200"................110.6...................... 114
.300"................148.6...................... 162
.400"................176.9...................... 204
.500"................195.9...................... 220
.600"................204.8...................... 229
price...............$2495....................... $1864 (exactly what I paid)

Gee, what can I do with an extra $631.00????? Where's this double the price stuff?

 

Just wanted to say that your price comparison against the 200cc AI heads is somewhat bogus. You are also getting a very high quality billet cam that runs $400, not just a set of heads.

 

You're 100% correct I overlooked that, i'll edit it.

 

It's pretty sad to see all this flow bench racing. What performs at the track is what matters... not what puts up #'s on a bench.

 

It is very hard to compare track times between 2 cars also. WAY more variables come into play when you do that. I always see people bitching about the price of AFR's but if you REALLY look around (and ask) there are deals EVERYWHERE on them. That's why I put up the side-by-side comparison including the price.

The flowbench numbers are the only quantifyable (sp?) measure out there that breaks down a cylinder heads performance with the least amount of variables. Swapping heads on a car while at a track on the same given day isn't really feasable.

 

Flow #'s alone are actually a very poor way to compare a set of heads.

 

I agree....

But flow numbers coupled with runner volume gives you a very good idea of whats going on.

A head that flows big air thru a small port is going to accelerate that race car like nobody's business....It's going to sixty foot and get the car moving much more effectively (the key to a low ET) and with similar (or even greater) peak numbers, make the big power upstairs to run a strong back half to also couple that low 60 foot time with a strong trap speed.

If were discussing road course racing a small efficient port is even more desirable...

-Tony