Hi.
A have a 400 build a while ago with all forged rot ***, and 11,5:1 compresion, Dart pro 1 200 ported to 1205, 2'' mid headers and 230/236 roller cam with LSA 112, and lifts .510/520.
Presently a have an LT1 well ported intake, with Holley TB 2x 58mm
The car is running not bad but it is not that i expected making 400 ci
let`s say bit faster than stock LS1 f-body
I`m wondering if the intake is maybe to small.... I dont really know if the LT1 is ok or should i scrap it and buy HSR, and will it make really difference?

I`m buck from our (F-body Club Poland) every year races, best time i make was 14.00 when Ls1 cars run 14.1-14,3 and hotcammed LT1 run 13,2 on a 1/4 mile.
I have a T56 and shitty 3,23 gears so all runs i have finished on a 3rd gear close to 6100 rpm, I know it was my first runs- so generally i can`t race but the car imho is a bit to slow also, or mayby it needs some more eprom tuning

thanks

 

Cam is a touch small for a 400. Heads could be abit larger but should work ok. I'd run a minimum of 236/242 with a bunch more than .520 lift for a hyd roller on a 400. Probably closer to a 242/248, but it should still make decent power with the current cam.

I'd look at the tune first. That motor should be running alot harder than it is, if its only beating stock LS1 fbodys. See where your at with timing and air fuel, then make a decision from there. Also need more gearing for that T56... 3.73 should do it for that cam size.

LT1 intakes are decent but really need ported to handle the big cube stuff. A 400 eats a ton of air. How ported is it? A miniram is abit larger version and flows more, and can be opened up alot more too than any LT1 intake. Not a bad choice for this motor.

HSR will likely help over the ported LT1 but its hard to say because a ported LT1 intake can make 400+ whp easily and from the sounds of it, your not there at all. I'd also consider victor E EFI single plane for this build. Also a fine option. You need the air flow those intakes can give although the HSR is really close to a miniram out the box

 

The problem is..... there is no such place to airflow an intake in Poland, i` mean there are in aircraft factory but it`ll cost more than the engine. To be honest i have one 236/242 cam with.555 lifts and 110 LSA, IT was running much bettr on it but i was not able to tune idle and part throttle even with wide band O2 sensor, so i decided to go wit a smaller cam.
I ported the intake, i`m not a pro but i was also not a first that i did, i reallly take a lot of material to fit the 1205


thanks

 

You had problems with the tune on that cam? What system are you using to tune it? It should beable to run fine, i've run cams like that on a 383 with Mass air flow systems. It may just need alot more tuning to really bring out some power in that combination.

 

there is a stock harnes from previous 305TPI with# 730, i`m just burning the 29c256eproms