Hey guys/girls I'm brand new to the forum and new owner of an 88 iroc 305 TPI (motor has really bad knock) so i'm planning on doing a 350 swap. I've read everything i could find after searching for 350 swap but my question is about which heads to use with the new 350 (sticking with the tpi setup). I talked to a guy at my local machine shop and he said he wasn't sure about the heads b/c of the tpi intake. He wasn't sure if 350 heads would fit b/c of the bolt angles. What would be a decent set of aftermarket heads i can use for my 350 build sticking with the TPI setup. If you could give me a summit racing reference number that would be awesome since i live 15 min from summit.

 

88Iroc,
What are your goals for the car? Obviously you're replacing the tired 305 with a 350.. Do you plan on building for performance or creating a daily driver? That's something to consider when deciding on heads.

I mean, theoretically, you *could* just have the 305 heads reworked with some larger valves and stick em on the 350. It's all about what you want to do with the car. Get it back on the road for cheap or...?

 

Truly I'm doing a restore project with my uncle (basically was my father) and good friend. It will be a daily driver during the summer non raining days lol. It' doesn't need to wheelie or anything i want a decent strong running 350 setup. I want a 350 b/c i got a block for 50 bucks (friends dad only had 60K miles). I know i need the injectors and the computer stuff but no one mentions about the heads. I want something a bit more then stock since I'm redoing the whole thing but it definaitly will need to be DDish. That a good enough response? If anyone has cam recommendations or any other recommendations i would greatly appreciate it. My uncles an old mechanic and I've been messing with engines for the past 5 or so years so its not like its going to be a completely retard trying this out i just want some advice from those that have done it price wise for the rebuild i'd like to stick around 2000

 

There are not a lot of high performance heads built with 87-95 bolt pattern intakes. Most of the heads are available for earlier 86-down and 96-up (very different Vortec) heads.

You can modify your intake to work with earlier 86-down bolt pattern heads, if you want. Then choices become vast. A good machine shop should be able to do that for you.

If you want a bolt-on, Edelbrock makes a true bolt-on head for 87-95 bolt pattern intakes (in the Edlebrock Performer series of heads). I think Dart might make some 87-95 bolt pattern heads as well, but I am not familiar with their recent product line.

 

I went down this decision path before. Keep TPI, go carb, which heads, intake, etc.. In the end I decided to go carb since my dad (an "old school" mechanic as he calls himself, lol) is more comfortable tuning carbs and we don't have emissions inspections here.

I did some reading on modifying the intake bolt pattern heads. There's a lot of information on that topic here on TGO if you search around. It seems to work perfectly for most people.

From what I understand if you do too many mods to the TPI you'll have to invest in some chip burning equipment and do a *lot* of reading to be able to get it tuned right. Personally, I'm a computer geek, so I have no problem with that, but... I went with what my dad said would be easiest for him since it is a joint project for us.

My project suddenly got a lot more expensive though since after the engine was torn apart and hauled ot the machine shop a crack in the block was discovered. *sigh* I used it as an excuse to just buy a 383 roller short block and start from there. :-)

 

THanks for the fast replies. I need to stay with TPI b/c of emissions testing. If anyone can tell me how to pass inspection without tpi I'm all up for it.

 

Well, like I said.. We don't have emissions testing here, but AFAIK you can't. You would have to stick with TPI. Visual inspections look for that kinda thing.

 

so jeff how well will those 305 heads work for if i have them redone.... i guess i could do a budget rebuild to get it moving and finish the body restoration then do a performance build once it hits the 25 yr e-check exemption. Will those heads be fine with a mild cam or should i just go complete 350 stock build?
thanks again for all the help guys

 

I don't want to discourage you from doing a performance TPI build! There are a lot of very knowledgeable folks here on TGO that will always be available to answer questions.

I don't consider myself knowledgeable, but more of a recipient of some great advice while doing my build. The people here are great. If you do nothing else, stick around here at TGO and learn!

Anyhow, as far as those heads go. I don't know what casting number heads those would be. If anyone else knows, please chime in..

Otherwise, you can get the head casting number easily enough. Just pull a valve cover and look.

The stock 305 heads will have smaller combustion chambers. That would score you some increased compression on the 350. I would suggest some larger valves if you decide to re-use them. I think they should flow well enough to accommodate a mild 350. As far as cam size before things break - I don't have any first hand experience. From what I have read the stock springs are junk and should be replaced.