spills

iTrader: (9)

Okay, Ill cut to the chase. I work at a Chevy dealerhip. We got SB's layin around like its nothin. I got a 4 bolt block thats gettin bored .030 over, just the basics. But for right now, I still got the L03 in the camaro. Ive been seein some conflicts of interest as far as how good the 305 heads will flow (if ported) on a 350. BUT, are the 305 heads on an L03 the same ones, the damn swirl ports? Can I jsut grind the swirls down and just smooth out the runners?

I know about 40% of the guys on here are on a budget as far as their car goes. I am as well, but I also have another DD, so down time isnt exactly a problem for me. Money, however, is. I wanna shoot for about 9.5-10:1 CR, runnin on pump gas, and preferably carb. I guess Ill have to lean the carb out to all hell before I get emissions, since it was TBI and all.

Well, so much for cuttin to the chase I guess. BUT, can I port out the L03 heads to flow "decent" on a 350 block? Semi-built bottom end, w/e heads I go with, DP intake, 650 carb, what kinda HP/TQ ya think itll be pushin at the wheels? Stock T-5, might change out the diff to 3.73 posi or something, gotta do some mroe research. Just wanted to get some expert opinions. Chevy guys I work with only know stock numbers, not modding n crap

BTW: all I know about the block is it came out of a truck, but the heads I wanna use for it are from my 89 LO3 TBI. Casting numebrs are still unknown yet. Raining like hell right now, are they gonne be on the head itself somewhere?

F-BIRD'88

Don't bother with TBI swirl port heads. If you expect to make any kind of decent power get some other heads besides TBI swirl port heads.

Other 305 heads can be modded and ported to flow "decently" and work well on a 350, but not TBI heads.
The ports {on other non-TBI 305 heads} are essentually the same as the ports on typical 350 heads but the stock valve size is smaller.
No, you can't just grind out the swirl vane.

Some good factory 305 heads to look for and port are
305HO pre 87 "416" "601"
305 TPI "081"

The nice thing about starting with a 305 head casting is they are usually cheaper to buy and they have a small combustion chamber. They have just as much power potential as a typical late factory 350 head you're likely to run into, once ported and fitted with larger 350sized valves. (1.94" x 1.60")
Their combustion chamber volume is typically 58cc's.
Once you've unshrouded the chamber for the new larger valves the chamber will be about 60-64cc's. Just right for a flat top pistoned street 350.

You have to remove a valve cover to read the head casting number.

spills

iTrader: (9)

Well, as it turns out, the block Im gettin comes with Vortec heads. It came out of a silverado, not sure what year, but everytyhing is stock. Are all Vortec heads the same essentially? I mean can I P&P em, get a decent size cam, and they flow good? Someone was tellin me that if I just freshin up the bottom end, put in a bigger cam, itll get the HP numbers right up there, so there aint a huge tq/hp difference (silverado's im guessin had a good bit of tq, but no hp.)

Stekman

Out of the box, they are factory heads. yes, they flow very well as that, but, like all other factory castings, they have their limitations. In their case, the biggest are the guide bosses needing to be milled down to allow for more lift so a larger cam can be used.

Yes, like any other factory casting, they can be improved. Port, polish, clean them up nicely, and you can squeeze some more cfm out of them. Depending on how far you take them 2.02 intake valves and 1.6 exhaust could be used. On my set, I just stuck with the 1.94 intake and took the exhaust to 1.6". Other things to do to them are screw in studs and guide plates. At the very least, pin the factory studs.