I have an 87 Iroc 305. I want to do work to the 305 bc it still runs and right now I am at a budget. I want to buy performace parts for the 305 and when I get a 350 I still want to keep those parts and put them on a 350. Are all 350's the same?

I was also thinking instead of boosting the 305 and since its old and I may just hurt it, should I just got for the 350 and work from there? How easy is it to swap compared to other motors? Can i still use the TPI manifold on a 350 and what would be the best 350?

 

I've asked similar questions and what everyone has advised is save the money and put it toward the 350.

 

Not all 350s are the same.

For that matter, not all 305s are the same.

Differences can be based on year (dipstick moved from driver to passenger side in 1980, 1-piece rear main seal came in 1986, center bolt valve covers in 1987, self-aligning rockers in 1988, etc.), induction (TBI got swirl port heads), and/or application (trucks typically got low compression and flat tappet lifters, while passenger car got roller lifters after 1987, etc.). Some of those may affect your swap, others won't.

One thing you can be sure will transfer from 305 to 350 is exhaust, and it will improve either engine. You can put in a better roller lifter cam in the 305 now, and it will transfer over to a roller lifter 350 block later. You can port your 305 heads and put in 1.94" intake and 1.60" exhaust valves and better valve springs now and the heads will bolt onto a 350 shortblock later.

'87 TPI will require '87-later heads due to the mount bolt angles, or else the TPI base mount bolt holes will need to be modified for '86-earlier heads. If you get an '85-earlier engine/block, the '87 flexplate won't fit it. Things like that.

 

If you haven't already, you could spend your "extra" money ion the chassis & suspension, so that you won't be risking wasting $ on engine parts. Once you do the 350, you'll be wanting a LS1.

Wheels/Tires/SFCs/KCA/PHB/Springs/Shocks/Struts/Fiberglass Hood/Seats/Carpet/Stereo/Etc. Etc. Etc. That much may not be as "exciting", but it certainly saves you $ in the long run by not buying parts that will just get replaced because you want something different & not because it broke. But when things break? Go ahead & buy the better Aftermarket version not just a stock replacement piece, if you can afford it at that time.

My car looks like hell, but runs & handles great, because I build it by doing all that I mentioned above.

 

You can port your 305 heads and put in 1.94" intake and 1.60" exhaust valves and better valve springs now and the heads will bolt onto a 350 shortblock later.

don't 305 and 350 heads have different cc heads?i thought of decking some 350 vortec heads and putting on my 1989 305 but then wouldn't they be too high compression if i later put them on a 350 block?

 

Need a few more Etc.'s.. Seriously!

 

PM sent

 

Yes. Typical 305 heads have 58cc chambers, and typical 80's & Vortec 350 heads have 64cc chambers. If you want to put heads on a 350 that have 305 size chambers, just up the piston volume by 6cc. If the 350 pistons that go with 64cc chambers give you the CR you want have 6cc valve reliefs (most are in the 4-6cc range), then for 58cc chamber heads, get pistons that have 6cc more volume total dish & valve reliefs (10-14cc pistons are pretty common).

 

This guy I work with is going to help me out. My brother was telling me get a 4 bolt main. ( I don't really know about cars so bare with me). Right now I want to do it cheap so own going to stick with a 350. Ls1 would he nice however its not cheap.

When I purchased the car the guy gave me performance suspension, tripod gauge, and other stuff. It has a flowmaster but its a single (the guy before him put it on and he doesn't know why). The car is in really good condition, no rust, interior is good. (I'll post a pic at a later time). There are things I want to change like the clutch, radio but I can wait, care about performance first