305 TBI to 350 Inquiries
 

Ok im kind of new to this, ive read a bunch of posts already about the actual swap, what im looking for pointers about is, what kind of motor should i get? Ive got an 89 RS 305TBI, and this car is a dog.. Im looking for something around 300 hp, and id like to keep the throttle body, and the LS1 is a little out of my price range. Plus i bet that swap would be a tough job. Any tips on where i could find a reasonably priced motor? Id be ok spending around 1500 +- i appreciate any feedback thanks

Re: 305 TBI to 350 Inquiries
 

Welcome to TGO

1) Learn how to use search - it is free and you'll find what you're looking for 90% of the time.

2) 305TBI to 350 TBI swaps are very common - there is a sticky that addresses many issues faced by many attempting such swap. Emission compliance should be considered when shooting for 300HP (rear wheel or crank shaft?).

3) For $1500 and depending on your local emission rules, stock L31 out 96+ truck with vortec specific intake (carb with TBI adapter), improved cam and exhaust should yield nearly 300 HP provided that you run higher fuel pressure and custom calibration. There is an extensive thread covering 383 build with Summit cam - look there for ideas and pointers.

//RF

Re: 305 TBI to 350 Inquiries
 

I was going to ask the same question.. I have a 350 out of a '76 vette, but I need some emissions safe heads (L98?) Our standards aren't too ridiculous, especially if you run cats..

Re: 305 TBI to 350 Inquiries
 

Kevman

I think you should look into a total combination - intake, heads, cam, compression, exhaust, emission equipment, and FI tune.
The bottom end typically is the easy part - just make sure that you have pistons that result in CC that is reasonable with matching set of heads. The challenge is to select a camshaft that has been proven (i.e. CARB certification). L98 heads should do just fine if you have them.

//RF

Re: 305 TBI to 350 Inquiries
 

I'm broke right now.. But I think the L98 heads would be decent for the emissions testing. My bottom end has a .002" clearance on the main bearings, it has been rebuilt recently. They are the 4 valve relief pistons, too..

Re: 305 TBI to 350 Inquiries
 

Oh brother - I know about being broke. Well, this when searching JY, Craigslist and freebies from friends become sources for a build. I am guessing that you have classic TRW flat top pistons TRW-L2256F30 with four valve reliefs - 6.1cc dish due to the valve reliefs. The aluminum L98 angle-plug cylinder heads have 1.94-inch intake and 1.50-inch exhaust valves and 58cc combustion chambers. Depending on head gasket the resultant compression might be on the high side. You have punch all engine variables into CC calculator.

//RF