Hey guys. I have gotten the lo3 out of my 91rs and am in the process of putting the stock l98 that i got off a buddy for a few hundred bucks. My question is will my lo3 manifold bolt up ok? I am getting a chip, larger injectors, esc and knock sensor. Any input definitely greatly appreciated.

Thanks

Bill

The L03 stock manifold is smaller than a stock L98 manifold. Get some headers...

If its intake manifold, I would choose a good carb manifold plus an adaptor, but you might be talking exhaust, in which case by some headers.

I already have headers and full exhaust on my car. I was just wondering if I could get by for now bolting on the intake manifold that I have do to lack of funds at the moment.

Bill

Yes, your good to go.

Steve

Steve,

Thanks for the reply. That is what I will do for now.

Thanks

Bill

Sorry man, I thought you were referring to the exhaust manifold. Yeah, stock 305 and 350 intakes are direct swap.

LOL!! No big thing bro. Thanks for the reply.

Bill

do you guys think that this will be a good base to start from? The L98 that it is.

thanks

Yes, the L98 is a better base than an L05 due to its better heads and cam. All factory TBI heads had horrible flow numbers.

Some LO5's had the L98 cam and recent evidence has shown that LO5 (193) heads are about on par with L98 heads. Both heads (as in all GM heads) have their flaws. The LO5 head outflows the L98 head on the exhaust but the L98 flows more on the intake. You sorta have to choose the lesser of two evils. oth heads respond well to porting but you may be able to get a bit more from the L98's. Either shortblock is a great starting point.

Shifty,

Thanks for the heads up? Oh yeah how much does it generally cost to do a head porting job?

Thanks

Bill

You can do it yourself for less than $150 which includes the porting kit and die grinder. Shops will charge $500 to $2000 for a port job. For stock iron GM heads I would invest in the stuff to do it yourself. There is enough tech data here on TGO to steer you in the right direction.

Shifty, what are you basing the head comparison on? Do you have flow umbers for a ported set of L05 heads? I would really like to see that.

As far as porting heads, if they are stock castings, do not pay someone to port them for you. It will costing you quite a bit. It really isn't difficult for a first timer. I have roughly 150 hours of porting time on a $9 Harbor Freight air grinder. I bought 2 new sets of Carbide bits on Ebay with 6" shanks for about $30 per set (each set brought 4). I spent a grand total of about $70 on mine, and I bought alot more bits than what was needed.

You'll find quite a few very good threads on porting from Sitting Bull, F'Bird-88, Vader, and a few other guys.