Horsepower for 69Z 302 w/#140 cam

**miket1** · #1 10-21-2015, 02:06 PM

What horsepower can be expected from a newly rebuilt 302 w/140 cam, chambered exh,, original exhaust manifolds, all other engine parts such as intake, heads, carb., are original to the car,

Thanks

**napa68** · #2 10-21-2015, 02:13 PM

Mike,

I think it may be a little soggy. Did you build this yet?

Tim

L78steve · #3 10-21-2015, 04:59 PM

My guess would be 350. That cam will move the HP up higher in the band so the manifolds will hamper output.

**William** · #4 10-21-2015, 05:38 PM

MCR September '87 did exactly this dyno comparison on a freshly rebuilt 30 over 302. It was professionally built, honed with a torque plate, heads milled to achieve 62cc chambers. Did 327hp/6750 with the stock cam, 347hp/6750 with the 140 cam. The 140 cam showed less power up to 6000 rpm. This was a street rebuild for a restoration.

Photos show the engine on the dyno with open headers, no fan or accessories, unrestricted intake. Your results may vary.

June '88 Hot Rod has dyno results from a 302 Traco built for the '68 Penske T/A cars. Shows just over 400hp/6800. Appears to have been tested with a single carb; cross-ram was good for another 40 hp. States an Engle cam was used.

Steven J · #5 10-21-2015, 06:49 PM

I don't know what the horsepower might be, but my brother owned a 70 1/2 Z-28 that was completely stock except for the 140 cam. It had a 4.10 gear, but should have had a 4.56 with that cam. It didn't really come alive until around 4000 rpm. It did have a great sounding idle, even with stock manifolds and factory exhaust.

ban617 · #6 10-22-2015, 12:25 AM

I would think in this day & age you could get a new cam made that would make more power and be more efficient .

**PxTx** · #7 10-22-2015, 01:36 AM

I think the stock manifolds are the big unknown. There are several popular combinations, but few performance paths w/ the iron exhaust. I would start by talking to Eric about a carb overhaul and I'm sure he would shed some light on what realistic expectations should be. He's run these mills on the dyno w/ all types of exhaust. Keep us updated in this thread on how you make out.

**Salvatore** · #8 10-22-2015, 01:55 AM

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: L78steve</div><div class="ubbcode-body">My guess would be 350. That cam will move the HP up higher in the band so the manifolds will hamper output.</div></div>

I think L78 Steve is pretty close.

**miket1** · #9 10-23-2015, 01:51 AM

The new engine is built w/replica #140 cam from Howards Cams, they say it is new technology w/smoother opening & closing ramps than the old GM cam, lash is .022/.022, It has 1 hour of break in time at fast idle from 1200 to 1700 ,, fine tuning the carb. & distributor the 302 is getting very crisp and idles down to 1000 rpm nicely, i need to adjust a couple things but so far it is running great.
I will not dyno the engine, just curious what approximate HP would be.

**Scott69Z** · #10 10-24-2015, 01:05 PM

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: miket1</div><div class="ubbcode-body">The new engine is built w/replica #140 cam from Howards Cams, they say it is new technology w/smoother opening & closing ramps than the old GM cam, lash is .022/.022, It has 1 hour of break in time at fast idle from 1200 to 1700 ,, fine tuning the carb. & distributor the 302 is getting very crisp and idles down to 1000 rpm nicely, i need to adjust a couple things but so far it is running great.
I will not dyno the engine, just curious what approximate HP would be.
</div></div>

Do you know how much vacuum your engine makes at idle? Are you running the stock 4053 carb and 480 distributor? I am interested in using this cam in my street dz302 but worried it will have idle issues and load up at idle. I really want to make maximum horsepower using stock parts.

Scott