Low 383 Numbers

[Skillet]

I bought my current Impala a year ago. It came with a Lingenfelter built 383. Pretty mild build: 10:8.1 compression, ported intake, ported aluminum heads, bigger valves. I was a bit disappointed with the dyno numbers but since I wasn't buying the car purely for the engine it didn't really bother me. Turns out the car had valve float. That's what you hear in the video and that's why the graph looks like it does. The car now has a new 230/236 cam, fresh springs, and an electric water pump. The heads are currently off since doing the spring swap revealed how bad the valve guides are and how loose the valves are. At least it sounds good in the video. Hoping to crack 400 next time out.


http://www.youtube.com/watch?v=jP3GLTxJ3VM

[1FASTSS]

Good luck on hitting your numbers.

[ls1dave]

i edited it because the embedding didnt work.

good numbers.

[Skillet]

i edited it because the embedding didnt work.

good numbers.

I was curious about that. It showed a box but it was blank. I thought I might have just needed a firefox addon.

[edcmat-l1]

I wouldn't be disappointed with that. They have a pretty heavy driveline, plus that angle boot intake don't help none.
I had a customer with a Callaway 383 IMP that made 330 RWHP. Took them dumb ass ram horn headers off it, put long tubes on it and gained about 20 rwhp. Put a cam similar to the one you have, and made 380.
Tuned a 383 F body, took the boot off, took the MAF off, ran it in SD, and gained about 25 rwhp.

[Skillet]

The only reason I'm a bit disappointed is from seeing H/C cars get real close to those numbers. I do hate those headers but the Tri Ys are big money that I don't feel like spending right now. Then again since it's laying down up top and those pulls were on a un locked converter so I probably left 10-15 on the table. I should have it back on the dyno in a couple of weeks and on the track the 18th. I don't think it will make 400rwhp but I hope it makes 400ft/lbs. I really don't care what it makes as long as it runs 12s.

[NicksTAgt]

Honestly with that cam and some mildly ported heads you should see close to 400, but your auto might choke that number down a little bit. Is your cam a comp 230/236? what are the specs?

[Skillet]

It's a comp cam XFI 476? 230/236 .576/.571 112+4. The heads are aluminum LT1 heads, ported and gasket matched. 2.0 intake valve. 1.56 exhaust. The intake manifold has also been ported and gasket matched.