CALL911

iTrader: (17)

My car;

1995 Z28

383 LT1(Lunati Sledgehammer Crank, Oliver Billett rods, custom Diamond pistons)
8.8:1 CR
Custom Camshaft 244/254 @ .050, .578/.578 lift, 114* LSA
Super Vic EFI intake
Kooks long tube headers
Custom Y-Pipe
Borla Cat-Back
ASM 58mm mono blade TB
60# Injectors
M6 w/Moser 12 bolt and 3.73's
FMIC
Meth injection
D1SC with 15#'s of boost
24x conversion


My question is, that given that setup, what would be the difference power wise between AFR 227 race ready heads, and AFR 227 competition heads? Given the lift of my cam (.578) the CFM difference between the two is 15 CFM according to AFR's website (at .550 lift).

I am trying to decide between the two and want to know if you guys think I'll see greater than a 15 RWHP difference between the two or not.

RamAir95TA

iTrader: (2)

The difference will likely be negligible and immeasurable.

NewOrleansLT1

About 15hp to the flywheel

Puck

iTrader: (17)

Being boosted with that relatively mild cam I don't think the extra port job will be worth a ton of power, but I'm no boost Guru so I would first ask guys with experience with boost and aftermarket castings.

IMO its better to get the base 227 castings for now, and have a porter with AFR experience like Tony Mamo or Craig Gallant get his hands on them later on if you want to make things a bit more nasty with a cam swap/port job. Craig did Sakura's AFRs and we all know how strong his car ran.

You already have the supporting mods and computer to get it done. AFR's have very strong exhaust ports and make ridiculous power boosted .

CALL911

iTrader: (17)

You're calling a 244/254 @ .050, .578/.578 lift cam "relatively mild"!? The cam is friggin' huge.

I know it won't make a huge difference in power. Volume is the biggest thing that will make a difference in the boosted world, but I am just curious for those that would have an educated estimate, what the actual RWHP difference would be.

15 HP to the flywheel has been guessed. Anyone else have an educated guess?

97Z28SS

iTrader: (5)

If you can afford the competition ones I'd get those because they will still make more power then the Race ready's.

CALL911

iTrader: (17)

If price wasn't a factor I would agree with you. However there is a substantial difference in price between the race ready and the competition heads, and I am trying to see "what kind of power difference" it will actually yeild on my car.

If its going to be 15 fly wheel HP or less, it is pretty hard to reason the extra $600. Now if we are talking 15-30+ RWHP, then it may be in my best interest to save up for the better competitions.

The big reason I am asking this is that I have a good deal on a set of race ready heads, and I just want to see what the difference between the competitions and the race readys will be on my car.

lt1needingboost

iTrader: (8)

i m curious are u still using the procharger fmic w 1 pump, if so thats gonna start holding u back. Are you using stock heads now? And if ur ? is with a boosted set up will u see more than 15 rwhp difference between these two 227 heads, i would say no u wouldnt.The difference might give u a pound of boost difference because of restriction, assuming theyre isnt more down the line for instance that borla catback do u run the one w/o muffler? As to the cam i beleive puck was refering to ur lift specs which i wldnt call mild but i certainly wldnt say thats huge i would guess most guys over 500rwhp are running 600 lift or better (not all but most), yes u have alot of duration, more than most. Hopefully thats help u out a lil bit.

CALL911

iTrader: (17)

I have never used 1 pump on my boosted setup. I have dual in tank 255 lph pumps. I currently have AFR 180 heads and am upgrading to the 227's. Hard reading a bit of your post, but I do have the standard Borla cat back, and won't be changing it.

I wasn't aware boosted cars where running over .600 lift regularly. Most seem to run lower (or so I thought at least).

I am not really looking for suggestions on my setup here. Just looking for the difference you guys think I will see between the two heads.

lt1needingboost

iTrader: (8)

I didnt mean to criticize just asking didnt know, i run a very similar set up w 215 heads the car that ran the blower before me ran the afr competition and he is the one who told me to go with the smaller heads stating w the d1sc he didnt gain enough with bigger heads to warrant it. So again sorry for the misunderstanding.

Puck

iTrader: (17)

Yes. On a 383 a 244int is not a huge cam at all. On a 350 I would consider it big.

If you are coming from 180s then either set of heads will be a big increase in power, but it looks like most agree that spending extra for the additional porting between the two will not be worth it.

While their factory porting is nice, hand parting is still the way to go so I wouldn't spend the extra money on the Comp package. If you are not happy with the standard 227s, save the extra 600 and put it towards a proper port job that will be worth more then the Comps would be.

Why don't you shoot a PM to Tony Mamo? He would be the best person to ask and I'm sure can give you an accurate guess. He has helped me quite a bit over PM, and I didn't even get my AFRs from him.

CALL911

iTrader: (17)

The 180's I have have shown time and time again that they are the choking point on my setup, and its due to their smaller volume compared to the much larger heads. If I had 210's I would have a harder time upgrading to the 227's. No worries on the misunderstanding.

I would NOT let Tony Mamo touch them. I have a buddy who had a very bad experience with his work. I won't go into details as it was not my car, so I'll just leave it at that.

lt1needingboost

iTrader: (8)

i do agree w u that ur heads are maybe a bit too small but i still dont think u will gain enuf too pay for the competition just stick w the cheaper ones, will you be going to a smaller pulley to stay at ur 15# of boost or are u just gonna see what happens and go from there.

CALL911

iTrader: (17)

Well, I'd like to see what peoples opinions are between the HP difference of the two heads before I decide for myself on if its worth the money.

The cars pulley combo is already the most aggressive that could be had (and that's where it will stay). Most people who max out the D1SC only see about 15#'s of boost. I have seen a couple make 17#s, and have seen where people have "claimed" to get 18, but most max out at 13-15#s. D1's can make more boost than D1SC's. Your combo besides the pulleys make up quite a bit at what boost level you'll actually see. Honestly, I wouldn't be surprised if after I do upgrade to the larger heads that I would notice a one to two pound drop in boost as boost is a measure of restriction.

Z8'S

iTrader: (6)

From reading this thread it has come to my attention that my heads are too small( 215cc) and my cam is too big( .700 lift and 268 duration) there is soooooo much more to it than 'those numbers',Talk to your head porter connection at LPE and have him evaluate your combination.

quik95lt1

iTrader: (7)

^ what he said.....im in his boat 26x duration .7xx lift with at 215cc head much more than interweb #'s to it

speed_demon24

iTrader: (6)

If you're still running a 3" borla catback with 600+rwhp that's the first thing I would change.

Puck

iTrader: (17)

I think the poor stock computer is what turned a lot of LT1 owners off from bigger cams, and the mind frame just stuck.

Most SBC guys won't bat an eye at a 260int cam on a 383, but a lot of lt1 guys go way smaller even on strip cars that barely see the street.

I'm all for baby cams and power under the curve on a street car, and loved my 227 in my 350 daily driver, but if its not a daily driver and you have the computer and mods for it then spin it high and let that thing eat!