jackdiamondback

Okay. I have been trying to figure out who makes an aluminum head for a 1986 305 TPI. The manufacturer sites are very confusing and I have yet to see a single head that actually says it is for a pre-1987 305 TPI. I see heads for pre-1987 302s and 307s, but not for 305 specifically. My car has had most of the emission control crap removed (air pump, etc.), although I am still using a single cat with Hedman Elite Ceramic Coated Headers. Maybe I'm an idiot, as my wife often remarks. Any help would be appreciated.

Stu

Morley

I don't think you're going to find an alum head made for the 305, it wasn't a popular engine and isn't economical to build one up. The 350 is the "flagship" engine for GM and most all small block parts you find are going to be for it. BTW the 327, 302, 350 & 400 can all use the same head, but because of the 305's much smaller bore it would need a head made just for it.

vjo90RS8

iTrader: (1)

the stock 416 heads that you currently have on your car flow pretty well. If they have alot of miles on them you might want to think about rebuilding them, having them ported, and machined for a bigger 1.94" intake valve. That is probably your best bet if you want to keep the 305.

IronbackTA

If you absolutely have to have an aluminum head on a 305, you can use the HO (ZZ4) aluminum head. (I think the L98 Vette head is basically the same, the HO head uses LT1 hardware) Use GM head gasket #10105117. Stay with the stock 1.94 intakes, you cannot go larger without hitting the bore. Check your exhaust matchup because of the raised D-port exhaust. You might have to elongate the mounting hole on your header to get a matchup. These heads respond well to a little pocket porting, port matching, etc. Standard head hop-up tricks. In stock form they're wimpy for a performance head. That's why they get a bad rap.
I did this to an '86 305 TPI using a small Crower cam and it more than held its own, even against 350s.
Do some searching, it's been done before, TPIS turned me on to using an aluminum head on a 305.

jackdiamondback

Thanks for the responses. If I went with a better iron head, what would be your recommendations? If I had the stock heads rebuilt, what can I do for maximum power increase? I had a 1980 Z-28 with an extreme 350 and would like to get this 305 to produce as much HP as possible. This was a one-owner car when I bought it three months ago and has 80,000 miles. It is mint inside and out. Also, how do I learn what the rear gear ratio is? I am new to this kind of thing since I just retired and have always had my HP work done by others. Now I have time to do some of it myself. Is there a stroker kit for the pre-1987 305? The ones I have seen are for 87-92. Finally, I have a stock GM HEI with an Accel HEI super coil. I had an MSD pro billet HEI on my 350 and will use this on my 305. Will the Accel coil work with the MSD (it fits on top of the GM HEI).

Stu

BatSipJet

http://www.speedomotive.com/sbc_305_...oker_crank.htm
this is what i found but i dont know much about it.

wesilva

iTrader: (35)

AFR used to sell a 305 specific under the part number 190SHST. It had the 190cc intake runners and 58cc chambers. Curiously it also had the center mount valve cover mounts. Like Morley has said, it wasn't a popular motor and the part was discontinued. They crop up on eBay from time to time and are a really slick head for any SBC looking for high compression without pop-ups. Mine were special ordered with the 2.02 intakes and 1.60 exhuasts and you can see, they barely fit in that 58cc chamber.

jackdiamondback

Reworking the Vortech heads seems like a lot of work and money and, as you note, could be problematic down the road after wear and tear. I am going with either the Edelbrock Performer (60909) or reworked LT4 Corvette heads from Powered Motion Products. This is GM part 12556463 from casting that ends with 8113. PMP will also do a pocket port and polish on their heads as a very reasonable price: $280.00.

Stu

IronbackTA

LT4 heads will not work with a standard TPI base. They have a higher intake port similar to Vortec or FastBurns. I think you have to plug water ports on the LT series head to run on standard cooling systems.

IronbackTA

For a cast head, World Products make a 305 torquer. See it here at the bottom of the page: http://www.jegs.com/cgi-bin/ncommerc...41&prmenbr=361

jackdiamondback

Ironback:

There's an outfit called Power Motion Products that has reworked the LT4 head for just this reason. Very reasonable price if you buy now--$900, $1180 with a pocket port and polish. Best cam I could find so far is by Engle Racing Cams. Hydraulic with .450/.450. The Edelbrock Performer and Performer RPM, which have the same valve sizes as the PMP heads, can't take more lift than this, so it seems that a roller cam is out since I can't find one with lift that's .450 or less. Also, someone on the web site had a pic of his 305 TPI with the PMP heads.

Stu

NjccBflo

alright, this is prolly going to sound very pathetic, but i like to call it 'thorough'...
in repair jobs, i've swapped GM parts from brand to brand to brand like no tomorrow, so long as it did the job properly (specs and all)...
in go fast goodies, can this still be done?
More specifically, the heads in question (elusive alum's for a 305) always listed as Chevy 5.0's... is it wrong to assume i can drop these on my 'Bird's 305?

jackdiamondback

I stand corrected about using the LT4 heads. In fact, the heads that will work are the LT1 Corvette/HO heads. GMPP PN 12556463. They must be from the casting ending in 8113. The combustion chambers are also 58cc and the valve sizes are the same. Chevy High Performance, in it's most recent issue, is building a 305. The one in the article is a 305 with throttle-body fuel injection, but the essentials are the same for the TPIs. They used a set of new cas iron Vortech heads, with the same valves and 58cc combustion chambers. These heads will work with a throttle- body and bolt up to the FI manifold. These heads bolt to the FI is apparently angled. However, the early model LT1s are made for TPI and bolt right up.

The CHP article said that they found that the Vortech 58cc chambers would not generate enough engine compression to run the kind of engine they are building. So, they milled the chambers to 53cc and bam--they got 9:63-1!! So, it figures that if 53cc worked on the CI Vortechs, it should also work on the LT1 heads. Am I correct? The trick to the higher compression they found was the milling and Fel-Pro head gaskets PN 1094. These are a very thin, rubber-coated steel gasket. Without the gasket, 8.8:1 was the best they could get.

jackdiamondback

Jeez, I just read my post. The CHP 305 is carburated, not throttle-body. The article explains that you can't use the aluminum head on a throttle body because of the change in the angle of the bolts to the FI unit.

LilJayV10

iTrader: (5)

First off, stay away from that 340 stroker, it's nothing but a waste of a lot of time and money, I helped do a 335 stroker, which uses a reground 400 crank. It's freakin ridiculous, I can't say enough negative things about it, it would be a lot cheaper to build a 350. I'm all for the being different thing, but there are better ways to spend money, IMO. Do a search in the archives, I had a thread about the 335 and all the problems.


Also, did I miss read something, but you can't use a LT4 head on a GEN 1 block because of the reverse cooling ports. Maybe I missed something in the post.

1MeanZ

iTrader: (9)

check out my sig. i will get my chip this week form pcmforless.com and then i am hittin the strip. i am guessin my car will go high 13s. the heads gave me great low and especially midrange power. i port matched the heads, polished the chambers and ported the heck out of my plenum and base. i got my heads ready to bolt on with roller rockers and all from a guy on a C4 website for 600$. all i added was a fresh valve job and arp head bolts. i like the swap, lots more useable power. talk to Willie, he has done this swap and he is basiaclly the one that talked me into it. i am glad i used the aluminum vette heads