355 Hp peaking really high
Thread Starter
TECH Apprentice
Joined: Dec 2008
Posts: 372
Likes: 1
From: Kinston North Carolina
355 Hp peaking really high I was just wondering if there are alot of 355 lt1 guys with heads, cam, and intake that the peak power is over 6800 rpms? I just reacently got my engine back in my trans am and got it on the dyno, and of course the opti crapped the bed on me. Couldnt get but one decent pull down, so the tune is still whack on it. What got my attention is the extremely flat torque curve it had on that one pull. At 6800 it still hadnt peaked on hp and torque was dropping at the same rate throughout the whole pull from 4600 to 6800 with peak torque being around 4700. I was a little dissapointed in the torque numbers which only peaked at 318 i believe. Peak power came in at 365hp, but with opti problems and untuned i figured that wasnt so terrible. The other 2 pull wouldnt even make it to 6500 because of ignition breakup so i just said to heck with it for that nite. My engine combo is ported stock heads with 185cc intake runners 8mm stemmed light weight valves pac springs and ls7 lifters with comp pro mag 1.6 rockers for the valvetrain. For the intake i cut the top off of it and ported it rather vigerously and welded it back together. Cam is a advanced induction grind which is a .613/.613 lift 22X/23X on a 108 lsa that i actually installed at 109 ica because at 106 it had 220 psi of cyl pressure which i werent so crazy about on pump gas. Now its 185 at 109 ica. Compression is 11.5:1. I am running a 3500 vigilante converter. Sorry this is so long. I was just kind of curious if there are alot of hyd roller 355 guys that are peaking at 7000 or more.
Last edited by wht97ws6ta; Apr 3, 2011 at 07:43 PM.
220psi should not be a big deal on pump gas, stock LT1s routinely top 200 even the iron head 10:1 compression b-body motors are usually over 190 on 87 octane.
Did you email Phil about changing the ICL the way you did? I thnk had you left the cam installed as intended it would have peaked closer to 64-6500.
Did you email Phil about changing the ICL the way you did? I thnk had you left the cam installed as intended it would have peaked closer to 64-6500.
Thread Starter
TECH Apprentice
Joined: Dec 2008
Posts: 372
Likes: 1
From: Kinston North Carolina
The heads are actually pretty conservative they only measured 185cc when i was done with them. The intake had a bit removed behind the tb and i spent some time shaping the runners to get some tapper in them as they approached the cyl head. I definetly wouldnt say they are hogged out. I butched another head i had to try to find a port that pleased me on the flow bench, so i done a little research before i went to town on my cyl heads thats on the engine.
Thread Starter
TECH Apprentice
Joined: Dec 2008
Posts: 372
Likes: 1
From: Kinston North Carolina
I would like to think so. It was also the first time it was on that particular dyno so it mite be a consevative dyno. I made 312 ft-lbs with the the stock engine with longtubes and a tune on RPMs dyno in garner north carolina.
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