hi i was wondering if anyone with desktop dyno could run a test for me to see how much power the parts listed would make on a bone stock 1974 390

Holley 4bbl 650 cfm carb
hooker competition headers
edelbrock victor fe intake manifold
and a good sized k&n air filter with ported and polished stock heads

 

dd just spat out 400 ft/lbs and 300 hp with that combo... there again, ive only been using dd fora little while so maybe one of the more experienced users can double check for you..

EDGE

 

Well Bud..Ya got a couple of thing wrong with this build....First off those are some nice parts!! Kudo's for you!! But ..Polished and ported heads wont do squat without a nice cam to let them breath as they should..and a cam wont do Squat without Bringing up your stock compression to help your Cam that helps the Heads that helps the Carb and the intake and the Headers!!

Your Cam is the Heart beat of your Engine....Match your Comp..to a nice cam and go from there.....

Whats the Goal of this build??

Russ

 

Alright, I'll run it for you. It's somewhat lacking IMO, but here it is: 348hp @ 5000rpm, 404ft-lbs @ 4000rpm.

If you want my opinion, you shold increase compression with a set of 360 pistons. Also have the heads milled down to 65cc, and have the intake milled to match. This would get you 10.1:1 compression. Then run a big cam, like the Crane 344621. This would get you 453hp @ 6500rpm, and 425ft-lbs @ 5000rpm. It would better match your other components, specifically your intake manifold. That cam recommends 10.0 - 11.5 compression, and you'd be on the low end of that, so I think you could still get by with pump gas.

 

I wish I could squeeze out +100hp with carb/intake/header mods, all without digging into the motor....
348 seems a little fishy to me, but then I don't use the DD stuff, just for this false sense if security.

My $.02's --Mike

 

thanks i wat thinking about that cam you listed it has a rough idle right? and i was going to try to get a 9.5 or 10-1 compresion. im still learning things i can do i am only 15 so if i get head work done and flat top pistons do you think i can run a big cam?i want one that has a really rough idle

 

Noticable, very noticable, rough, or extremely rough?

 

rough like you can really feel the revs and boddy shake but nothing that has to have the compresson over 10.5-1

 

how about with this crane cam? 348801 and all the stuff a listed and flat top pistons?

 

The 348801, although a good cam, is a bit mild for what you're trying to do. It also has a big dual pattern, meaning that it has a much larger duration on the exhaust than the intake. This is good for stock unported heads, but for ported heads you'll want to close this up a bit. The one I listed is much closer to a single pattern, and I think it would work a lot better with stock heads. Crane lists it as fair idle, which really means it will sound choppy. They list the 801 as good idle. The 344621 that I listed has lift that wont be too much for a stock setup either. If I had it to do again, it is the cam I'd probably go with.

Edit: Here's the specs for the 344621:
296* intake / 300* exhaust duration
.554" intake / .563" exhaust lift
Description: "FAIR IDLE, PERFORMANCE USAGE, GOOD MID-RANGE HP, 3800-4200 CRUISE RPM, 10.0 TO 11.5 COMPRESSION RATIO ADVISED. BASIC RPM 3000-6200"

Here's the specs for the 343801:
278* intake / 290* exhaust duration
.548" intake / .580" exhaust lift
Description: "GOOD IDLE, DAILY PERFORMANCE USAGE, MILD BRACKET RACING, 3000-3400 CRUISE RPM, 9.5-10.75 COMPRESSION RATIO ADVISED. BASIC RPM 2200-5200"

 

Maybe he should just call a cam company and have them make him a custom cam.

 

Why? I found him a good one!

 

Isn't the main thing that affects idle quality is duration and overlap...??? I would think he would want to look at a cam that has at least 222 (maybe a few degrees more) on the intake side.

 

That first sentence/question doesn't sound right (bad choice or order of grammar).

 

Were your heads professionally ported and polished? What do they flow?