which head woul dbe better?

[Swims350]

ok first off the 305 heads are old school like pre centerbolt type, and I have to find the numbers and run them to know the exact specs.

I think they are 58cc ones and 1.94 valves.

ok so the question is this...

with my 350, yes 3 5 0

I have a set of tbi 5.7 heads now, center bolt style, again have to run the numbers again to know the cc and such.

compared to running the old school 305 heads.

street truck, 4x4, going to run 4.10's later, th350 trans, pretty much everything stock for tbi setup, may change cam later.

I know the 305's will increse CR and give performance a bump, yet some say they won't flow good enough for a 305 much less a 350.

others I thought had said the tbi heads were good for torque?

just looking for some opinions and info. I'll have to run numbers later. Once I can pull valves covers and get them wrote down.

 

[Swims350]

nobody?

 

[skysurfer]

I thought Jim would jump in here so I was waiting for his input.

Nothing wrong with the swirlies for a stockish engine. They're good for low end torque but they dont flow well beyond 4500 rpm so if you have any thoughts of a big cam and a heavy foot don't bother with 'em. Some guys have massaged the swirl port heads and had decent results, but it's easier to slap on a set of Vortecs and call it a day.

 

[Swims350]

iit may be but not when you're on a tight budget. having to find, buy and then buy an intake to go with vortec's aint too cheap.

I can get the 305 old school heads for free, and I currently have the tbi heads.

I was thinking of buying a port and polish kit and do the 305 heads since they need valve seals anyways.

for now stockish cam, and probably intake, but I can get a performer for a good price and was thinking of cam swap later to a nasty sounding one, was actually looking into a 230 duration at .050 and .480 lift, with like 109 or 108 LSA.

 

[Jims86]

The big issue wit the TBI heads is really the limited cfm(430 i think) of the SBC TB Unit. With TPI, I was buzzing the TBI heads beyond 5200 with no issues.
The TBI truck heads can benifit from porting work, like any head, but Bumping the exhaust valve to 1.7 wakes these engines up pretty good, and using the L31 Roller cam compliments these heads nicely, while still keeping torque figures in the low range for truck use.
And yes, 305 heads are 58cc, 350 are 63.3.

 

[Swims350]

ok now another question, if I wer to swap in a bigger cam, would it benefit me to advance it or maybe retard it, and by that I mean the use of a 3 keyway crank gear?

I'm a little in the dark about cam advance and retard, and was gonna read up on it sometime when I had internet access or time to do so from another computer.

also would advance or retard of a cam this way, how would it effect the idle of said big cam? take out the lumpy bumpy or leave it?

 

[Jims86]

ok now another question, if I wer to swap in a bigger cam, would it benefit me to advance it or maybe retard it, and by that I mean the use of a 3 keyway crank gear?

I'm a little in the dark about cam advance and retard, and was gonna read up on it sometime when I had internet access or time to do so from another computer.

also would advance or retard of a cam this way, how would it effect the idle of said big cam? take out the lumpy bumpy or leave it?

Here is link 'splainin advance and retard.http://www.compcams.com/Pages/413/cam-timing-lobe-separation-angle.aspx
BTW, there is a mamber in NC getting ready to dump his Q jet for TBI, i put the bug in his ear that you ar lookin.

 

[Swims350]

yep q jet would work fine for me. I got a stock q jet intake and some 305 heads with an hei dist. but no carb as of yet.

 

[bucket]

Wish Ida known before, I have a pair of 305 heads that have been ported already. They do need seals though because they've been sitting unused for a decade.

 

[Swims350]

the ones I'm going to get have to be worked too, they need ported, and they definately need seals because it smokes.