Looking to get stealth ram for my trans am gta. I see on holley there going for $3000 for the entire kit. But do I have to get the wiring harness with it? How much how of a gain can I be expecting in horsepower?

 

You don't need the extra stuff, just need the intake, plenum, and fuel rails which should only be $600 or so.

I've heard 50+ horsepower but I have nothing to back it up in terms of dyno charts or anything like that.

 

You can adapt your existing harness very easily. You will need a tune for it to run right. Here is an article from super chevy swapping from tpi to a stealth at the track as well as a dyno tune. http://www.superchevy.com/how-to/0307htp-hollley-stealthram-intake-third-gen-iroc/ Really depends on how well tuned it is to see how much increase you get. Also you can piece it together or get a used one for less. There is always the Professional Products version dubbed "Chinese HSR" there's a thread on that one as well. I got mine used with all the hardware for $400. Just make sure you get the newer style after 2005 or 06 so you can port up to a 1206 gasket.

 

If you already have a TPI car, with the small dizzy then nothing needs to be done to the harness. Everything will plug in.

As for the power gains? On a stock L98 its worth about 50hp around 5500rpm, but the actual peak gain is smaller, maybe 10hp. You lose the TPI torque hump around 3500rpm, the torque flattens out and carries on higher. Up until the stock heads and cam choke it out.

The HSR doesn't so much give you more power as it instead moves the powerband up about 500-700rpm on a stock engine.

 

you're correct. on a stock motor there isnt much to gain from a HSR, but stock TPI systems start to limit power gains with cams over 200 degrees of duration @ 0.050" lift. and lift around .420". so about stock 350 specs or to 4,500 RPM peak power. if you add a bigger cam the stock TPI system will rob your horsepower because it wasnt made to support more horsepower, as a matter of fact the TPI system was actually designed for a 305 GM just never changed it when they started adding TPI's to 350's. the HSR starts to shine with real upgrades like a bigger cam and heads. ive seen 400hp TPI engines turn into 500hp HSR engines with just an intake swap but they usually have 200cc intake runners on the heads and 240+ duration @0.050" lift cams and 383 cuic inches or more. and if you are using a HSR on 87 or newer F body then you should have a small cap distributor. but 85-88 came with a cold start injector that the HSR doesnt have a provision for. this isnt an issue if its 40 degrees or warmer but if its colder its gonna not wanna start. if you have a 89 and it looks like you do then you all you need is a modified tune

 

You are responding to the wrong person here. I haven't had an L98 for about 7 years now. I moved to an LT1 and more recently heavily modified at that.

 

i just agreed with you and the rest of the info was intended for red_89_gta