WHAT DO YOU ALL KNOW ABOUT RUNNING 305 HEADS ON A 350? IT LOOKS
PROMISING! BUT WHAT CASTINGS # TO USE? AND WHAT ONES TO AVOID?
AND WHAT IS THE BIGGEST VALVE COMBOS I CAN USE?

 

I believe there is a guy by the name of clutchdust here who is using a set, not sure of the casting #'s, and he really like them....... :cheers:

 

I'm not sure, but I think you would get a "truck" engine. You would have small valves. Probably severely restricted breathing. It might increase low end torque, but would probably be "all done" by 4500 rpm.

 

Why would you want to do that. The 305 heads have tiny valves and don't flow worth a darned. The only plus is that they have small (58cc) combusion chambers that would boost your compression. But if you want a cheap performance head that will boost your compression go with some Vortec heads, they have 64cc heads (62cc actual) and will out flow just about any stock Chevy head (except Fastburn.) They are cheap too! You can usually pick up a set used, with self guiding rockers for $400.00. With another $220.00 you can get a Performer Vortec intake and have the valve guide bosses trimmed down, and springs that will handle a cam with up to .525 lift.
For a budget build up they are hard to beat.
If you are interested, I'll sell you a set complete with rockers and center-bolt valve covers for $400.00, I have a brand new Performer Vortec and GM resusable intake gaskets that I'll sell for $125.00. Plus some other extras I'll throw into the deal. I'll even meet you in Houston to drop them off.
They are in great shape, I was going to use them on my 69 350, but I went with a ZZ4 crate motor instead. My 350 was in terrible rough shape, so I didn't want to take a chance of adding high performance heads to it and totally destroying a numbers matching block. Sorry, I didn't mean to make this a selling effort, but another good choice would be a set of 64cc chambered camel hump heads. Just about any of the earlier pre-smog heads would be a better choice than 305 heads. IMHO.

 

checking in! i have 'em. love 'em. you need to get the right ones though. i bet your asking because you have a set and your thinking about putting them on. right? for a very cheap 'rebuild', man this is the ticket. you can get these heads for next to nothing and where SM is right is they have 58cc chambers which will give you a major boost in CR. if you have a weak smog motor with that whimpy 8 or 8.5:1 CR, the head change alone will put you up to 9.2-9.5:1 :yesnod: where i disagree with SM (with all due respect) is there are some 305 HO castings that have 1.85" intakes (the ones i have :D ) that will well outflow the infamous '882' castings and equal to just about any pre-vortec 1.94 heads. hog them out a little and they will flow more than enough to support a mild cam (262-274* range). if you do a search for the thread, i went all into it about two months ago. the head change, fresh rings and a used cam (about a 268*) netted me a 40+ hp gain as measured before and after with a gtech. not too bad for a total from teardown to restart of >$500. :thumbs:

 

This is an old reply I made that I copied and pasted. Too much to type out again.

"I have a set of 14102191 castings on my car now. They are 88-up gm "swirl port" heads that were used on efi trucks mostly, as far as I know. I think the 193's are the same thing. They came with 1.94/1.50 valves on 5.7L rigs and smaller (1.84?) intake valves on 5.0L's I think. Anyway, the info I've been able to collect on them is a little sketchy, but what I know is that mine are 1.94/1.50,64cc chambers(had them cc'd by machine shop),and are pretty plentiful and an inexpensive way to bump compression on stock 8.5:1 engines. My machine shop only charged me $200 for a reconditioned pair, including the centerbolt valve covers. They are not super high flow because of the "vane" which is cast into the intake ports(hence "swirl port"), but they work fine up to 5000rpm's, and the swirl is actually supposed to promote more complete fuel amotorization and enhance low end torque. One major thing, the center two bolts on each side of the intake are at a different angle than standard 86-prior heads, and you need to modify these corresponding bolt holes in the intake to get the bolts to seat. I have a 2101 Performer, and I basically notched out my center holes with a hack saw and used a bigger flat washer on the bolts. Sounds a little Bubba, but it's really hardly noticeable, and they seal up just fine. Anyway, that's about all I know. Found a little more info by doing some forum searches on Chevy truck sites. Bottom line, they were available, cheap, and an easy way to score a compression point and get the cooler(my opinion) center bolt look for around $200-250. I later got a set of new, unused stock ZZ4 valve covers off ebay for $15 with the later model nicer looking oil fill caps. To get back at your original question, they are a fine stock replacement/upgrade to replace 882 or similar castings(with 1.94 valves,not neccesarily 2.02's), but I do not believe they have the practical ability to ever perform like vortecs or other after market heads at flow figues above .400" lift. Hope this helps. My current setup sounds about like the build you're talking about. I wish I had moved up to a 214/224 cam, or something like an XE262, especially since I changed from 3.08's to 3.70's and got the converter, but what I have works real good, and pulls 18" of vacuum @ 650rpm. Good luck."

 

I've got a set from an '89 Sub 350 EFI....probably like the ones ORvette described above. I'm trying to get rid of. Nothing wrong with them, the engine never leaked and never smoked.

Len

 

There are only two numbers of 305 heads that you would want to use. They are 14022601 and 14014416. These both have 184 intakes and 150 exhaust. All othere have 172 intakes. With dish pistons, these will move your compression over 9.5 They are a good inexpensive little hopup if you can find a good set. Around here they are hard to find as all the circletrack guys like to use them. Hershey :chevy