Need help with cylinder head comparison

[65-72 chevytoys]

for a stock rebuilt 307. I need some opinions please see why here

http://67-72chevytrucks.com/vboard/s...56#post2207056

[AR15DEFENSE]

do you have desktop dyno? I used it to pick out cams for a few different engines and ave always been happy. I have heard it is accurate to within 5% of actual on an engine dyno..? if you want it PM me, I'll send it over

[67 cst swb]

I voted WP Sportsman II's
...because you already have them,
Now, take the $ you were going to spend on heads and go buy a rebuildable 350. You'll be way better off in the long run. your mileage may be better with a 350 than a 307 (???? not sure) due to you be working it less. A 350 compared to a 307, even with the same components, will end in way better and efficient results... Plus the cost of rebuild would be same or cheaper for a 350 due to more common piston/ring set up.
Also, the less "overlap" you have in the cam selection the better the mileage, as well as keeping your highway cruise RPM in the 1800-2400 RPM range...(i.e. Rear Gear choice)
Just my .02 cents

P.S. Actually, I think you need my stock 307 heads, SOOOOOOO, I'll trade you straight up for your WP Sportman II's.... DEAL???? I'll even pay shipping... hehehehehehehehe

[jeffspower]

You will be soo much happier with more cubes.

[CrashEd]

200CC runners are a lot for a 307.

[65-72 chevytoys]

Is 200cc Too much air flow for the 307? That is what I am concerned about and actually performing worse than a smaller intake runner head. However, my budget has tightend and I am trying to make do with what I already have. A short block 307 with the WP heads on the workbenck. I would put the 400 in it except I still have to get it machined and internals just to make it a short block. However, with the 307 and heads I can get a cam intake and carb, or am I just way out of the park on making this work???

[Billla]

200cc runners for a 307 would be way, way overboard. Intake velocity would be way down, and you'd end up with a gas hog with really poor throttle response. Heads and cam are all about airflow; for a 307 you need to adjust your reality a bit in terms of how much you can stuff in a 307 vs. a 350 or larger. At 100% volumetric efficiency, you're only able to use about 533 CFM @ 6000 RPM. I have no doubt the magazine 307 made 315 HP - but I bet it was a screamer at 6500 RPM or better. This doesn't synch with your desire to build the 307 for better gas milage

There's nothing wrong with a good 307 build for the street, but the only reason I can think of for a high-performance aftermarket head is if you think at some point you're going to swap them to another engine. Your best bet IMHO would be the GMPP small-port Vortechs if you don't already have an intake manifold, or failing that just a good set of rebuilt heads from a local/online source. If you feel the need, you can do a little bowl clean-up and a good port match - for your intended usage, a solid pair of iron heads is more than enough. Looking at the other thread, this is the same advice RJ22 gave - and I completely agree.

You should expect somewhere around 240HP and maybe 340TQ; the HP peak will be a bit high for a pickup, as will the torque - but it'll be a nice smooth driver and with some smart tuning give you the gas milage you're looking at.

The one closing comment I'd make - and it's been made before - is that unless you're doing something wild, SBC displacement all costs about the same for an overhaul. If you want the 307 for some small improvement in fuel milage and because you have the parts - all good. If you want to build a really strong enging, then a 350, 383 or your 400 would be a far better choice for the $$$

[65-72 chevytoys]

Thanks Billa I was hoping you would post. The flow number is what I was afraid of. I think I will change direction yet again depending on what I can find for some smaller heads.

[itsmike2k]

Back about 10 years ago i had a 307 w/ world sportsmans, 64cc heads.. I had a performer rpm manafold and cam with a turbo 350 manual VB and a 10" vega stall. It ran really good for a old short block, i didnt do anything to the short block just bolted on my parts from my blown 383.. But it was worlds different when i bolted everything to a built 350 w/ forged flat tops. I loved those heads!! So they will work and it will have power.. Just depends on what you wanna do...