Hey Guys,

I just ripped apart my engine and now I am about to put it abck together (After replacing a few things of course). But first I would really like to know what kind of power it is making right now. So if somebody could run this through Desktop Dyno, I would really appreciate it. Here are the specs:

350cid .040 over
Flat-top pistons with 4 small valve dishes (sorry don't know the name of these)
Pocket ported 76cc heads (#333882)
Crane Cam number 278 H10 (specs here, look at #5: http://www.cranecams.com/master/apps/chevy8.htm)
Edelbrock Performer Manifold
Rebuilt Q-Jet
Heddman Headers
Flowmasters

I hope this is enough to get an estimate on whether this is enough or needs a couple of better parts.

Thanks for the help,
-Max

 

Come on guys,

Can somebody at least give a fairly accurate guess-timate. I don't want to realize that a better cam would net me 30 HP or something after I pop the engine back in.

I realize its a big pain in the a** to put all that info in but I would REALLY appreciate it.

Thanks,
-Max

 

About 350 hp.

Use a dual pattern cam like the Comp XE262 or Crane PowerMax 272, however, as they can help a lot with the exhaust flow.

 

I'm gonna say about 340HP

According to Dragstrip Plus... If you slap in some 3.73 gears and a 2800RPM stall you may be able to see 13.4 @ 98mph in a 3400lb car (with driver).

I don't have exact details on your combo so thats just an educated guess. Dragstrip Plus has always been within 2 tenths of every proven combo I've run through it.

EDIT: The XE262 should give you about 10 more HP. The major restriction of your motor will be the #882 heads. No matter how much work you put into them, they are still junky smog heads. From what I understand they are also very prone to cracking. (correct me if I'm wrong).

 

Because of the 882 heads, 280 HP max.

A stock 350 with those heads, 929 cam, intake not too different from the Performer, dished pistons, made 180 HP. I don't see any more than 100 HP above that in your list.

Get some decent heads, and just throw that 882 scum in the trash now that you've used them for your practice in porting heads. Then you'll have a chance of making some power.

 

Thanks for the help guys,

I figured that the 882's would be the limiter, but are they really as bad as you say. My only other alternative is to port the heads from my 86 305TPI. Would the TPI heads with a pocket port and larger valves yield better results then the 882? Possibly 325HP+?

Thanks,
-Max

 

They can be made to flow somewhat better, and are alot less likely tp crack. However they absolutely would need the bigger valves, and their chambers are only 58cc so your compression will be like 11:1 with those on top of a flat-top 350. 305 heads pretty much belong on 305s because of that.

The cam you picked is OK for a street motor with the other parts you list, but it won't matter much as long as you strangle the motor with heads that don't flow.

 

Yes the 305 TPI heads will be much better.
Your compression ratio will not be 11:1.

When you machine out the chamber wall for the larger 1.94 valves, your combustion chamber will end up being larger than 58cc. More like 60/61cc. Consider 1.60" exhaust valves too.

A set of Ported 305 TPI heads with the larger valves will work way better than 882's.

Your actual finished compression ratio will depend on your piston deck height, gasket volume, and final chamber cc.

You can download a compression raio calc from
www.download.com search for "engine cr"

If your piston deck height is .045" (common) your cr will be under 10:1 with a 58cc head.

Putting 305 heads on most 350's does not result in a exessive compression ratio.

Don't be shy with your porting , these heads can be turned into quite a fair decent street/ strip performance heads once you put the work into them.

 

Thanks for the help guys,

I'll pull the TPI heads tomorrow. One more question, I don't have any of the tools for porting so how much would a simple port job and overhaul (new valves, vlave seals, etc..) of the heads cost at a machine shop?

Or is it cheaper to just rent or buy the tools and do the porting myself? (assuming its relatively easy to do)

Thanks,
-Max

 

"According to Dragstrip Plus... If you slap in some 3.73 gears and a 2800RPM stall you may be able to see 13.4 @ 98mph in a 3400lb car (with driver). "

That seems too ideal. I normally see 13.4s with about 6 more mph than that. Ever compared what this program guesses to real times?

 

You can buy a Sears die grinder from Sears -$100
You can buy carbide die grinder bits from many industrial tool supply places. You'll need 1. 6" shank cylindical shaped cutter with a roulded end and one 4" shank flame shaped cutter
not real pointy.
The stones can be bought from the same places or where ever they sell air tools etc. The sanding roles can be bought from many speed shops or jegs.

Check the Summit Catalog.

The work is not hard but is time consuming.

 

The lads have steered you right about the 305 heads. Excellent potential, as good as Vortecs. Follow the link at the end of my sig for a how-to with pics

 

i'd guess around 260.