I have the option now to have either my new 350 tbi crate motor heads machined free or my 305 heads....would I get more compression from the 305's or go with the 350's.....ive got the cash for the cam but thats it, so no other mods been learning about the lt4 hot cam and the zz4, now I get the free machine work , so any ideas????

new 350 tbi,1''tbi spacer, headers,3'' dual exhaust, th350 tranny,3:73 gears, accel this and that,cold air induction, completly stock engine

 

For sure the 305 heads--AS LONG AS THEY ARE NOT TBI ALSO.

All TBI heads are to be avoided due to casting inferiorities. The compression will go up but that might be a blessing. You'll have to figure that one out.

Have the 305 heads fitted with 1.94 intake valves and then port them according to the instructions at the end of my sig for lots of extra fun

PS You will have to get the spring seats and valve guides machined to use those high lift cams like the ZZ4 and LT4. And I don't think a TBI engine will like them very much ...

 

d--m the 305's are tbi heads, off a 92 rs

 

Then off to the wreckers with you and get a set of 081 305 castings. Cost maybe $40

 

lg4 right????pops own junk yard....why I got so many f-bodies and other toys

 

ive never beefed up a fuel injected before, this is my first to try, im not much of an idiot (much) just trying to make sure about stuff, everything else I got is carbed if it aint stock efi,not alot of money to spare either, so trying to make sure bout things

 

Oh man, you ARE laughing then!

Since you have a roller-cam block, the only LG4 heads that will work are those from a 1987 model, since that is the last year they were offered in Camaros. Post-1986 305 TPI heads are good, too. (Pre-1987 LG4 and L69 heads are 416 and 601, but the bolt angles are off.) Just look for a casting with 081 as the last three numbers and you are in business. Those are the 305 TPI and LG4 heads from 1987 and up.

For that matter, if you have a set of 083 L98 heads in the yard they already have 1.94" intake valves. Otherwise they are virtually identical to 081 heads.

 

l98 are vette heads arnt they????I know he's got like a 88 or 89 vette sitting out there, wether he lets me rob it or not is a dif story

 

but for the 87 up camaro's....mostly robbed, might have 1 early 87 gta

 

The Vette L98 heads are aluminum but the Camaro/Firebird ones, the 083s, are cast iron.

An 87 GTA would have at least a 305 TPI, I think. Them's the babies!

And if the TPI setup is still on it, why not just swap it in and do away with the TBI? It is vastly superior.

 

dont wanna go there... had to sell my tpi setup on my 92 a while back..hjdfbgdfbg!!! neede $ but had a tbi crate 350 sitting around that I was going to put in my 72 gmc truck so as sacraligous as is sounds I stuck it in my 92Z28 minus tpi350, as for tpi setups of any kind...yeah right, them suckers were picked at long time ago

 

What about a carb? They are so much easier to tune and don't have $500 sensors that burn out.

 

I guess its more like a challenge...carbs are so easy ya know, well easyer anyway, just wanted to at least say my 92z is fuel injected and leave it at that if anyone asked, cause with being a Z people are going to assume its still tpi if I say fuel injected, and my feelings wont be hurt so bad, its my baby

 

Then you definitely want to talk to the knowledgeable folks on the TBI board. Basically, the TBI units on small blocks don't flow much more than 400 cfm. A decent 305 or 350 wants at least 600 cfm to produce good power. There is a tech article on this site called "Ultimate TBI Mods" and using it some folks claim to be running 305s in the high-13s! It shows you how to modify the TBI to flow a lot more air.

Imagine the look on their faces when you pop the hood and show them they were just waxed by a TBI!

 

I come here cause I never seem to get a reply in the tbi boards, as for the ultimate tbi...did it

 

adding that I have the tpi induction with cold air still on it,and the tbi mods seemed to have no big affect

 

That is doubtless because the engine still can't use that extra air. It will NEED heads, cam, headers and exhaust to use what it now has on tap.

 

Sitting bull, why the hell are you recommending he look for a set of 305 heads to work on and port. Just starting with a decent 350 casting is a much better idea. No point in buying a set of boat anchors.

 

Ed,

I told him that several replies back. If you look up the thread you will see this:

"For that matter, if you have a set of 083 L98 heads in the yard they already have 1.94" intake valves. Otherwise they are virtually identical to 081 heads."

But he is getting all his machine work done for free, so it doesn't really matter. Lucky dog, eh?