[jmichaelre]

Building an engine on a small budget for the first time, heres the specs any ideas on possible Horsepower? All parts are fresh including the heads. I know that most would say not to put money into these heads, but I had a local college do all the machine work for free.

350 bored 4.030
using stock crank and rods
flat top pistons 4 valve reliefs
block decked (took .020 off)
72cc chevy heads 1.72I 1.5E milled -.010
z28 valve springs
edlelbrock performer intake
edelbrock performer plus cam Duration 278/288, Lift .420/.442
Holley 650cfm

 

[techinspector1]

Do you know the piston compression height and crown configuration or can you provide the piston part number. I understand you said flat, but there are some flat-tops that have a recessed crown that is shorter than the crown at the perimeter of the piston.

 

[jmichaelre]

heres the link for the part at summit
http://www.summitracing.com/parts/TRW-8KH345NCP30/

compression distance is 1.56 is that what you mean
+5cc piston head volume

 

[jmichaelre]

Also forgot to add this... Head Gasket, Composition Type, 4.166 in. Bore, .041 in. Compressed Thickness

I'm guessing around 9to1 compression but i could be wrong

 

[Plaintoast]

If there is ANY way you can get rid of those heads, I'd highly recommend it.
Something with 1.94 intakes would be much better. If you can't locate anything, check craigslist for some 305 heads with 1.84 intake valves, that would be a step up and cost very, very little. You could probably find a set from a running motor, stick new seals on them and your springs, and bolt them on. (I'm assuming this is a budget build, correct me if I'm wrong).

 

[Rustydawg]

Ran your engine in Desktop Dyno 2000:

271 HP @ 4500 rpm
380 ft-lb @ 2500 rpm

This is assuming small-tube headers, 9:1 and the Performer cam.

 

[jmichaelre]

I'm going to replace the heads when i have money saved up, as for now these heads have new seals, seats, guides, and springs also this his a 4x4 chevy with 3.42 gears....do you think my choice on a cam is good...im trying to be conservative...also thanks for pulling up my numbers on the desktop dyno.....I do plan on buying headers along with heads down the road just need this thing running good here soon.

 

[Rustydawg]

Perfect cam IMHO, wise to be conservative. Just for kicks I ran your combo again with some 882 iron heads (151 cc intake), here's the results. Some Vortecs would be even better.

326 hp @ 5000
394 ft-lb @ 3500

the torque curve looks much flatter and broader with the 1.94s, no surprise. I think the server is too busy to let me upload it, If you're interested I can try later.

 

[jmichaelre]

Wow another 50 horses just with bigger valves and higher flowing heads. I didnt think the difference would be that big, however if this truck is general between the 2000 and 3500 range will I really ever see those horses? Also, would the numbers be even greater with a pair of vortecs, or am I confused is that what you already ran?

 

[Rustydawg]

Yeah, it's not hard to see gains in power over the small-valve 1.72 / 1.50 heads.

I ran the 2nd simulation with small block 882 castings, Vortecs would be better still. There are tons of heads out there, I just grabbed one to illustrate the difference.

Note that the HP and torque peaks moved up by 500 & 1000 rpm respectively going to the better heads, so your point is valid - with your truck you won't see the gains much at part throttle.

Keep in mind that Desktop Dyno was written by a committee of optimists, "real world results may vary"!

 

[Blazin72]

how did this get posted as a "Read Me"? Does this mean this thread is never going to go away?

 

[straightshot350]

desk top dyno

Ran your engine in Desktop Dyno 2000:

271 HP @ 4500 rpm
380 ft-lb @ 2500 rpm

This is assuming small-tube headers, 9:1 and the Performer cam.

Hey this might just be a pain in the butt so if you don't want to no big deal but would you run my motor on you desk top dyno?
sbc 355 stock crank 9.1 c/r with aluminum heads.Combustion Chamber: 64cc
Intake Runner: 190cc
Intake Valve: 2.02"
Exhaust Valve: 1.60
a lunait hydralic cam 276 duration 504 lift 2200-6400 range and 1.6 rockers
1 7/8 tube headers wit 2.5 collector and a demond 750 cfm carb. Thanks for your time.