Firebreather

The exahust in my car sounds kind of raspy. It annoying. I mean not all the time but at certain revs it does. The best L98 I've heard has Flowmaster though, but it has a custom y pipe and exhaust routing. I think it has something to do with the bending over the rear axle. Any ideas?

JR92z28

I have a question since most of you have L98's.
Do you or anyone you know have vortecs on an L98 motor?
Which flow better when ported-polished, bigger valves, and better springs, L98 Aluminum heads from 90 and later or Vortecs?

Thanks,

White91GTA

the vortec heads are a reverse flow head. when you put the vortec heads on, you also have to change the intake base to a vortec base because the vortec heads will not bolt up correctly with the regular tpi base...i am assuming you are tpi is this correct?

JR92z28

Yes,

I was asking with a ported stock L98 base and L98 heads -vs.-
Vortec ported base and Vortec heads- all under TPI setup which would flow better?

camarojoe

The Vortec heads ARE NOT reverse-flow cooling heads like on the Lt-1's! The reason you need a different intake is because of the different bolt pattern that these heads along with the GM fastburns have. Vortecs are SBC Gen 1 heads, not Lt-1/4 style heads.

JR92, check out 1Bad91z's posts to find out about ported Vortec heads. They kick butt.

JR92z28

Thanks, camarojoe
I know about the Vortecs and the different bolt pattern. I also know that they are not reverse flow heads. I also have read all of 1Bad91z's posts, and I know what these heads are capable of.
I just wanted to make sure I was right about them flowing better than L98 Aluminum heads.

Thanks,

cronsformula350

they're pretty good heads, but the intake holds more power for fuel injection, tpis released a mini ram with vortec bolt patterns, its more expensive, but would yield more hp than a really wicked tpi intake. edelbrock victor jr 23*, flow 260-270 cfm out of the box, they conservatively rate them on flow. I have a buddy with a mini ram, and brodix track 1's reworked that flow 300 cfm at .600 lift, in an 88 iroc'z, with long tubes, a cage, full interior, 9" ford out back with 4.11's, turbo 400, and a 3" true duals to the tailpipes, and runs 11.00s, borederline high tens, and can run in the 9.90's on spray(he usually can't hook up).

So you don't have to abandone gen 1. heads, stock cast iron L98, can be reworked to make up to 380 hp for new valves, and a major increase in flow, when used with a mini ram or stealthram, 380hp is the more for peak hp. If you get L 98 aluminums you can push it up to 410 with 11:1 compression.

White91GTA

Thanks for correcting me, I knew the LT1 heads were reverse flow but thought i had heard someone say that the vortecs were too...you have just taught me something