[blackflag]

I'm in the process of building a 408 iron block for my new stock suspension /275 car. My goal is to run mid 5's for a while then step it up a couple seasons from now.

The top end setup I have went 5.40's in a 3400lb fbody and my new car is 3200 25.2 99 camaro. Only difference is that engine was a 440 and mine is a 408.

Based on what I understand, about 250 is the limit on these heads due to the thickness of the decks, is that about right?

Here a quick rundown of what I'm working with:

Stage 2 L92 heads that flow 340/220 (done by mike duke)
Custom bullet nitrous cam
Cary intake
Pro Systems dominator
Monte Plate
6.0L iron block
Callies Crank
Lunati Pro Rods
Diamond Pistons -4cc
Distributor conversion
Harland Shaft Rockers

Motor should make real good power on a 250 hit, but I'm not sure if I could safely push it with more than that without changing heads.

Is it worth o-ringing or doing other mods to the block/heads for nitrous? :smt102

I know mid 5's doesn't get it done in x275 so down the road I'm going to need more power to be competitive. But for now I just want to go race it locally and have some fun.

The car is the orange Fbody on Burkhart Chassis home page putting it on the bumper and has been 5.20's with a BBC/F3 so I know the suspension works.

I know that the best setup would be a 6 bolt block/heads but I already have all these parts and want to go racing this season when I can finish it.

 

[ShiznityZ28]

The limit is your tuneup. we have never pushed water on 4 bolt heads stock or aftermarket. timming pushes water not nitrous. what you will find if the tuneup is good and the pistons are worth a damn etc. you will run out of what you can get in there on a given rpm. and more jet gives you little to nop more. on our 396 we found about 400rwhp nitrous and more jet did not help. advertised nitours company hp it would have read like 550 or so. not saying that is the limit but where we found our limit. if the car is making less than optimal hp on them otor than the extra nitrous hp could be more.

More often than not the tunup is the limit.

FYI i didn't read your stuff so this was a quick "theory" post