I looked at some charts and dyno's that "compared" stock TPI to the HSR and other intake mods. What i noticed however is that the high gains were only on engines with a cam and heads. SO technically wouldnt the heads be the real weak link to the TPI system. If avg. gains on a runner/base combo are 20HP and gains for simple vortec heads gains around 40hp wouldnt that lead me to believe that more of the restriction is in the head. Sure HP will always be lower than TQ with the TPI runners, but that was the way it was designed. I want to work around that design and make it better. So for that heads would be my best bet would the not. Also if anyone has any other promising mods on their mind please tell me.

 

If you are not attempting to extend the rpm range that the engine operates in, then the cylinder heads may help with a cam change that offers a close lobe seperation and longer lobe duration. If you are attempting to extend the operatin speed, the only thing that will help that is some type of intake change with shorter/larger runners.

 

TPI works well the way it is, the heads and intake work well together, you could go alittle better of a cam as long as you keep the power band in the right range,


its like anything, you can throw parts at something but if they don't work together, meaning same powerband and what not, you aren't going to see the increase you would if it was a matching combo,


you wouldn't put a 3500-7000 rpm cam with a dual plane intake on a 305, with 184/150 valves, an 850 carb, with 1 1/2 primary headers going to single 2 1/4 exhaust would you?

 

exactly i dont plan on going much past 5500rpm, I like the power where it is - low. So im thinking about a heads/cam/rocker combo. I want to use the Vortec heads since im on a budget and im only looking for moderate power gains. What would be a useful cam lift/duration for the heads?

 

I don't think that intake will bolt to a Vortec.

 

someone sells the base that will bolt directly to the vortec heads. seems like i saw it in Jegs or Summit.

and yes heads are a restriction on the TPI motors. if you're looking for decent power, upgrading the heads and cam will definately wake the car up.

but as stated, watch what cam you get because obviously you don't wnat one that kicks in at 6000rpm.

 

you can get the base but its not cheap, for the cost of the Vortec heads, and the TPI base with Vortec bolt patern you could be into a set of aluminum edelbrock heads,
and personally I'd take an aluminum edelbrock over an iron vortec any day

 

The edelbrock E-tec heads...for an emissions TPI car require buying the vortec base plate as well. WHich would cost me more than the vortec heads and the base.