I'm new to the GM camp too - first time owner of a performance car of any kind and I love it.

So, with the 305 TPI, which I have and am pretty fond of even if it's not got the bigger cubes, what are the biggest compatibility problem areas between the 305 and the 350?

I already understand that heads from a 350 you have to be very careful - that, or they just don't work. What about stuff like cams, cranks, etc - which main internal parts are compatible and which arent? I guess the bottom line is I'm still learning about the small block and I don't yet know what parts are exclusive to the 305 and which ones are used on both the 305 and 350.

I've been thinking about rebuilding my 305 - I don't want to go to a different block for more cubes because I want the car to have matching numbers. BUT - I've been thinking about blueprinting, maybe even stroking the 305. Has anyone heard of a stroked 305? Don't even know if it's something that can be done. In planning what I might want to do, I keep finding that I don't know which parts will work on the 305 when in the catalogs it just says "SBC" - so, any input here would be great.

Thanks all, Kevin

 

Well first off, welcome to TGO and welcome to your new lifestyle. As for starters, I sugest you read all you can in the tech articles on the opening page of this website along with the rest of the stuff on the side bar. Just a thought so that you can familiarize yourself with third gen camaro's and firebirds.

350 heads will work only after extensive milling the block and heads. See, the 305 has very small bores compared to the 4 inch bore of its bigger, more popular sibling. The 305's is 3.766 or somewhere around there. Now 350 heads have a larger combustion chamber then a 305's, and the valves are not so grouped like they are in a 305, so what will happen is when the valve is open, it could hit the top of the engine block. That could cause MANY problems you dont want. Cam's, cranks, etc... everything is basicly the same. the 350 and 305's stroke is the same 3.48 in stroke. Now, just to let you know, all TPI is the same on a 305 and on a 350 except fuel injectors and a few sensors. Any cam, header, intake, and valve cover that goes on a 350 will fit a 305. They are both small blocks.

If you do plan to stick with your 305, rebuilding it is a good idea. People are gunna come in here and say, "by spending all the money on a 305 rebuild, you could of gotten a 350 block and got that rebuilt" but it seems you wana stay with the mighty 305. Stroking the 305 is heavily debated here. Tunedport335 has done it, and PM him to talk to him about that. Powerhouse makes a 305 stroker kit. SBC=small block chevy=262-400 ci blocks and greater. The SBC has gotten as big as 454 cubic inches, which is usualy a number reserved for big blocks, but now with new technology blocks made by World i belive, they can make them pretty dang big now a days. Plus, it looks like a small block, so you can say.."Yep, its a 305 alright! Just have headers and cat back!". Anyway, Usualy the 305-350 is grouped together in headers and exhaust set ups and you can see them. I sugest giving your car a tune up and doing basic mods to the suspension and drive train before you get into the engine. Nothing sux more then to have a hi-po motor and tearing apart your 700/5spd or 10 bolt. I hope that helps you out some there. Take a little tour of TGO and read up one some of the stickeys and what not. You can usualy find your info by doing that. When you have a problem or what have you, post up a thread, and we will come to your assistance. Good luck and again, welcome to TGO!

 

Yea you can stroke a 305 with power house's stroker kit. It raises the cubic inches up to 335. I heard though that they dont make very much power over stock anyway. But if I was goin to rebuild my 305 I would deffinatly put the stroker kit in. There are alot of people who flame this idea but its all on the owner to do what he/she likes. The big thing with the 335 stroker is that u have some serious cam issues hittin the crank. You cannot run a very large cam cause then the lobes hit the crank shaft rotating weights. Though someone on this board put a big cam in their 335 and just ground away the rotating weight so they would clear the cam. I dunno how safe that is but it worked! But to see real gains you need to port ur heads, people have gotten LB9 heads to flow better than stock 350 heads from goin crazy on porting. Then another thing to look at is when doin a stroker, is that strokers need air and lots of it so U want to port as much as u can to feed it the proper amount of air. TPiS here in minnesota is one of the greatest places to turn for high performance TPI stuff. They'll help u out where needed so u dont screw anything up. They are on the spendy side but take it from me they are worth it. (not everyone will agree though). But they make large tube runners that will make goobs of torque for u if you want ur stroker to do what its supposed to. I say do the stroker and let us know how its goin.

Jason

 

bigals87z28, Fbirdta878787-
Thanks for the info and the warm welcome! I've been perusing the site daily for over a month or so now and reading like crazy. I've also purchased a couple of books about the TPI system and one specific to 3rd gen f-bodies that have been really helpful.

So, it's pretty much the rule of 305'rs - stay away from 350 heads. I read some where that people have machined the upper portion of the cylinders to accomodate the bigger chambers/valves - somehow that doesn't seem right - seems like that's the one place in the cylinder that you would want the most material to avoid catastrophic destruction of the cylinder walls.......

So, if 350 heads are a NO, then does one work over 305 heads or look to the aftermarket? I've only heard that World makes 305 heads - are they still making them and are they any good? Could I basically "make" a set of World heads with a very careful and thought porting job of GM heads?

I'm glad you guys seem to see where I'm coming from - I just think it would be fun to keep the stock engine and work it over. Right now, I want it naturally aspirated too - not really interested in a blower or NOS. See, I think it would be fun and challenging to take the stock engine and blueprint and balance it very well, do what one can to it through cam work, valve train work, and porting along with maybe some electronic mods and the use of high quality parts and try to get every last drop of power out of it that way - simply by improving upon the GM design, as it were. It's sort of like me saying I'm setting limitations on cubes and induction and then the goal is to get as much as I can out of it with those limitations. And of course, it has to be as durable if not more so than from the factory. Just me I guess.............

Bigal - it's funny that you mention doing a tune up and suspension mods - part of that has already been done and part is in the works. I already did a complete tune up - with 77k, I figure best to start from scratch. I put on a new cap and rotor, Bosch platinum plugs, MSD 8.5mm wires, new O2 sensor, new serp belt, new fluids all around including tranny and rear end, and of course a good grease job. The clutch had some chatter in it when I got the car so I decided to replace that while it was still working - a sort of preventative measure I guess. I'm putting on BMR control arms and an adj Spohn track bar just in case it gets new springs or new treads.

My plans are just coming together - at the heart of it all though is I want it to look outwardly original and have matching numbers and mostly original parts simply because it's an IROC - one day, the nice IROCs will be a rare thing I'm sure.

So thanks again for the welcome guys and do let me know what you think about 305 heads too.

C-ya, K

 

305 heads, you have a few choices.
Porting your heads
I sugest you port the intake and exhaust runners, bigger intake valve (1.84 to 1.94), and have them mill the head for added compression. You can port the runners yourself with a die grinder, but the rest you need done by a shop. Then you can add whatever new valve train parts to your heads.

the World 305 SR torquers are basicly all that i decribed above, but for near 800 for a set. Thats a lot for just some 305 heads. they used to be cheaper, but I dunno, last year they skyrocketed another hundred bucks. You can buy them bare and make your own, but it doesnt matter. They are the best bolt on heads you can get

Vortec 305 heads require a lot of work also, including milling and porting to flow with the world heads. But you cant beat vortec head design. Only problem is, you need to get a different intake for the vortec head design. Thats extra $$$.

Then you have the aluminum corvette heads that will fit. These are the only 350 heads that will fit a 305 due to its small chamber. It flows better then the stock heads, and you will shave a couple of lbs off the car.

With all the heads, I sugest you think about a cam shaft. Several good cam chafts can be gotten from comp cams, and gm performance. Im going with a ZZ4 cam with possibly ported stock or if i can find them, ported SR heads.

 

Welcome to TGO. Here is some good reading to keep you busy:

https://www.thirdgen.org/techbb2/sho...ck+Replacement

https://www.thirdgen.org/techbb2/sho...&highlight=305

https://www.thirdgen.org/techbb2/sho...&highlight=305

https://www.thirdgen.org/techbb2/sho...&highlight=305