How much HP?

Lightingrod · #1 (**permalink**) 03-13-2011, 03:30 PM

What engine and how much HP/TQ is everybody running?

I just built a new engine, 388 SBC with AFR 210cc race ready heads (2.08"/1.60" valves), 10-1 compression, Comp 280AR solid roller cam, rev kit, Edelbrock Performer RPM intake, Holley 750 or 800 cfm dbl pumper. The block has been decked and squared, KB ICON forged pistons, eagle forged H-beam rods and crank, internally balanced.

Looking at similar builds I think it should be in the 500-550 range on both HP and torque. With a pretty flat torque curve peaking at around 5000 and max HP in at around 6000. This should be a good 150 hp more than the current iron head 383.

I'm taking bets on how long the 700R-4 is going to last! It was built by Bulldog Transmissions and I'm going to upgrade to a full manual valve body!

Should be fun!

Al

vector1 · #2 (**permalink**) 03-13-2011, 05:11 PM

i have something similiar with 9-1 comp, and it is a shade less then 500 hp on engine analyzer sim program using an old performer rpm manifold, showed about a 50 hp gain using a vic jr. rpm air gap might be the best of both. max tq was 4700, max hp was around 6000.

Tim Brewer · #3 (**permalink**) 03-13-2011, 08:16 PM

I won't rag on you for running a chevy and an automatic, but I will tell you this...most EVERYONE is disapointed at the dyno. But you need to find yourself a dyno to put your car on if you really want to know your true HP and torque.

vettestr · #4 (**permalink**) 03-13-2011, 10:09 PM

Al,
Until the fat lady sings and you dyno your Toy true HP and torque numbers are only a guess. More important from my point of view is whatever the numbers are will the car do what you want her to do.

The absolute secret to long life of a 700R4 is proper TV cable adjustment. I am a big believer in setting the points with accurate pressure readings. Keep tranny temps in the normal range with a cooler if needed.

The car is lite enough combined with the first gear of the 700r4 that it should be lots of fun light to light. Choose the rear end gear to keep her buzzing in its happy RPM range and the almost 30% overdrive of 4th gear lets you relax on a freeway. I still like a manual tranny in a Cobra but an auto has a few benefits.

Hotfingrs · #5 (**permalink**) 03-14-2011, 03:33 AM

IMHO 4.11 gears coupled with the 3.06 first gear ratio of your trans will make first gear worthless. You've got way to much rear gear.

Lightingrod · #6 (**permalink**) 03-14-2011, 07:15 AM

Quote:

Originally Posted by vector1

i have something similiar with 9-1 comp, and it is a shade less then 500 hp on engine analyzer sim program using an old performer rpm manifold, showed about a 50 hp gain using a vic jr. rpm air gap might be the best of both. max tq was 4700, max hp was around 6000.

I had both an RPM Air Gap (Dual Plane) and a Victor Jr. (Single Plane). I went with the Dual Plane RPM, though some friends and builders tried to talk me out of it! From SIMS, the dyno results of similar engines, and my own experience (BBC). It seemed to me that if peak HP was under 6500 the dual plane RPM was a better choice for the street. With my heads and cam I think it was borderline and I could have gone either way. I went with more mid range torque with the loss 25-30 top end HP.

vettestr/Tim Brewer

All true about dyno numbers, even an educated guess is still just a guess and small differences can sometimes make big differences in final numbers! Friends and even Comp Cams recommended more cam and the Victor Jr intake, I went the more conservative route!

As to the 700R-4, the TV adjustment is everything and you must check pressures! I'm going with a "Full Manual" valve body, no TV required but I will check line pressure!

Hotfingrs

"IMHO 4.11 gears coupled with the 3.06 first gear ratio of your trans will make first gear worthless. You've got way to much rear gear."

I think you may be right but it should be FUN! Even with the current engine I run drag radials all the time!

Al

CobraEd · #7 (**permalink**) 03-16-2011, 05:18 AM

Quote:

Originally Posted by Tim Brewer

I won't rag on you for running a chevy and an automatic, but I will tell you this...most EVERYONE is disapointed at the dyno. But you need to find yourself a dyno to put your car on if you really want to know your true HP and torque.

Don't forget a chassis dyno will be about 18% less than crankshaft power, so you need to factor that.

.