Mrbowtie26

iTrader: (3)

I currently have a 402 ls2 block with AFR 225 heads, fast 90/90 etc... I had to get the block repaired because of the ear that the outer starter bolt bolts onto the block broke off. I finally got around to pulling the engine to have it repaired and I am now thinking of going a different direction. The heads are AFR 225's that were originally the larger chamber versions (72cc ? maybe) that were milled to around 62 cc I believe. I think they are best for a 4" bore arent they ? Anyways I was thinking of purchasing a LSX 454 short block, a blower cam, and a Magnacharger type blower. Are my heads perfectly fine for that application or will I need to get ones setup for the larger bore ? Also the motor would be going into a 2000 TransAm so the Magnacharger would need to fit under the stock hood and cowl. Is this possible or would any charger that fits under the stock hood be too small a displacement for the 454 ? Any links to the best blower for my application would be appreciated. I'm thinking a combo like this would be around 700-800 fwhp. Does anyone have this same combo or one similar ?

DeltaT

iTrader: (5)

IMHO a 454 will be so powerful down low that a centrifugal blower would be a better setup.

Jim

Mrbowtie26

iTrader: (3)

I think your probably right, for some reason I just have an itch to do a roots type blower. The cool factor is much greater imo My main issue reading up on some of them is that the ones that are of a larger size just won't fit under the cowl of a 2000 f-body. Was thinking of a Mag 122 or a KB but i dont think the KB would fit. Are there any other roots type blowers of that larger size that will fit under the cowl with some minor cutting involved ?

calongo_SS

iTrader: (7)

I don't think you'll find a roots blower that can feed a 454 and fit under the cowl of an f-body.
454 ci with a lsx block is recommended for N/A apps only, but their are people boosting them. It's probably a little risky.

elias_799

iTrader: (8)

i would go with a turbo, you will get almost no lag with a 454 if your aim is only 800whp, you just have to size the turbo properly. and i believe a 454 has a bigger bore size, so it would be better if you can get a head that has a combustion chamber close to the size of the bore. good luck

farmdawg

You might want to get some heads with bigger combustion chambers to be more boost friendly. It could be done but I think bigger cc chambers would be better. With a 454LSX the MP122 may even be too small, and I don't think there is currently a kit for the F-bodies out there, yet. There are some in development currenlty I'm sure, but not released yet. Any roots type blower setup on 4th gen F-bodies is gonna require some cowl modification to fit, and some hoods require some modding too, not all but some. I really could have modded mine to fit better, it only had about 1/8" clearance and there was some damage from the motor rocking and wearing into the hood even with poly mounts.

Mrbowtie26

iTrader: (3)

If the 454 is too much displacement what if i use my current 402 ? Only thing is it's been a while since it was built and I dont recall all of the specs. I think the heads were milled to between 62 and 66 cc and the pistons were -7cc pistons. I dont recall the head gasket thickness. The block was one of SLP's High compression ZL402 blocks. I'm thinking the comp. was around 10.5 to 1 - 11 to 1. I have to look this **** up when i have time lol. Anyways if the boost was intercooled would I be ok even at 11 to 1 as long as i didnt go over lets say 6 psi ? and if so what power approx should i make with my current AFR 225 heads and a mild blower cam. 600 rwhp ish ? Thanks for any input.
Ron H.

Then again maybe I should just buy a smaller displacement short block and boost the **** ouuta it. Ahh the choices ......

elias_799

iTrader: (8)

if the compression is 11.0:1 then 6 psi is the max i would run. but i would lower the compression right now because you engine block is probably already out of the car, and we all know that once you start boosting an engine you will always want more. so i say drop the CR now and save yourself allot of hassles.

LS6427

iTrader: (2)

Your goal of 800 RWHP will be easy with the 402 and an S91 turbo. EASY!!!

ls1290

iTrader: (20)

A maggie can barely feed a 383.

98Z28MASS

iTrader: (6)

+1 on turbo or centrifigal blower. Maggies are great but 402/454 is too much engine IMo for a maggie to be efficient. You would have to look into a larger roots/twin screw blower like the whipples or KB's, but those def wont fit your stock cowl.