Ok, I run 13.70s in my nearly stock (air foil, 1 5/8 block huggers, dual Flowmaster 2.5, and a home brewed CAI) 1990 Corvette L98 with a T5 and 3.42 gears in my Nova. I want to run faster (low 13s/ high 12s) and was looking for mods that might not affect my drivability too much. I was thinking AS&M runners, ported plenum, 1.6 RR, and maybe a different manifold. Do I need more mods like valvesprings/cam to go this fast?I don't want to kill mileage too much, so any help would be cool.

 

i think the runners, base, and RR, should be good for low 13s. cam and ported heads might get you 12s.

 

The AS&M runners, ported/aftermarket base & plenum, AFPR, 1.6 rockers should get you close to that I would think. Changing cam would need bigger valve springs yes and it's always good to change out the guides when you do this. Do you have the aluminum head?

 

1.6 RR's will help. They add a bit more overlap, you will notice the difference since you have headers to take advantage of the overlap.

An edelbrock large tube base and AS&M large tube runners will really liven up your TPI after 3500 rpms. Though they are rather costly added up.

If you do get a cam, make sure its a single pattern cam. The corvette heads have D-shape ports which flow very well. So they don't need a cam with extra exhaust duration as a cruch.

Porting the heads is also an option.

 

Nitrous won't effect mileage, and will net you 12's.

 

Thats the easy way out though

Basically, mostly anything engine related that is not a cam will keep your mileage the same, give or take a mpg. If you were going to do the intake, I would take the time to do some porting on those heads, you can really open them up, and it would compliment the intake very nicely. Take advantage of a custom burned chip from somewhere like pcmforless.com to further help match your computer to what has been done so far. You can expect at LEAST 10HP there, and some guys have gotten over 20HP.

 

If you pull the intake off to change it you're already half way through a cam swap or if you do a cam swap you've already pulled the intake off so you almost may as well do as a pair. I'd expect decent gains with a home ported base and a ported plenum, even without the runners (although I'd expect a good bit more with all 3) then a cam and a chip to take advantage of it all you'd really be moving!

 

I did his chip. It rules.

 

I was hoping to be the first to say Nitrous but I missed it so let me second that notion. It doesn't eat anything when you're not using it, and it's addictive like a drug when you do use it.