Hello ladies and gentlemen. So I picked a new to this weekend, it's and '85 Trans Am 305TPI. All stock running gear aside from a can and roller rockers. Supposedly one of the heads is cracked and leaks coolant into the exhaust. I suspect that the car had a bad thermostat, as there is RTV everywhere on the t-stat housing. My last TPI car I swapped to carb. This one, I think I'm going to keep TPI. My uncle has a 305 that used to live in a hobby stock circle track car with tricked out 416 heads and a big dollar rotating assembly. I'm thinking about building this motor, rather than upgrading to a 350 as I can snag everything ready to assemble for $750. When it comes to TPI I don't know a whole lot about tuning them for performance so I'm going to ask for some input. I know that they are not great for high RPM power in stock form. I'd like to have something that's capable of 6500RPM or so. I'm planning on doing a port match and polish on the intake. What should I do with runners and plenum? Or should I go aftermarket? What about cam selection? I see a lot of guys running the 2032 cam, is there something better? And what about tuning the ECM? I understand there are some hardware limitations to the '85 ECM. Is it worth upgrading? Is it possible to have my setup dyno tuned after it's all put together or am I stuck having a chip burned and hoping for the best?

Sorry for so many questions, but I'm a carb guy so all of this is pretty foreign to me, so I thank you all in advance for any advice!

 

For 750 you can't lose. Enjoy the build while blowing dome Stangs off the road! Ps. All the articles I've seen use carbs to get the HPs up. But that's no fun. The TPI seems to be a torque monster. Most races are 0-60 so who cares. Have fun!

 

Thank's man. I'm usually a carb guy due to the ease of tuning, but I really don't want to molest this car a whole lot since it's pretty clean and original. All old parts (Motor, trans and rear end) are going into storage after I swap them out. It's just going to be a cruiser/playtoy so I'm not worried about making huge power. If that was the case, It'd get that 406 I was planning on building!

 

That car looks really clean - nice grab!

 

If you want it to make power to 6500 forget the TPI

 

Even on a 305, north of 6k is going to be a tall order for a long runner intake.

What do you want to do with the car? How much power do you want to make?

 

Just make sure you change the rear gear, no matter how you build the TPI. Not sure what you have in the car but a 3.23 or 3.42 works great.

 

Thanks! It is very clean, especially for an Ohio car. No rust, only damage on body is that dent in the passenger door. Paint on the hood and driver's side is a bit faded and cracking in a few spots, but it's eventually going to get painted.

It will be a street car, might see an occasional autocross or trackday. I don't really have a power goal in mind, just want to maximize what I have in the car.

I haven't checked to see which ratio it has, but it is a 9-bolt with one of those 2. I have a 10 bolt with 28 spline axles, Torsen and 3.73 that I'm going to put in it. Was building it for my other car but I decided that one is going to the scrap yard.

 

Maximizing what you have would be installing a set of 113 casting corvette L98 heads, mild cam, headers, fully ported stock base and plenum. My 86 ran 13.40s at 101mph with a 5spd and 3.23 gears on the stock tune with those parts.

 

That's basically what I plan on doing. I already have a set of 416 heads that have some port work done to them, 1.94 tulip valves and have been shaved just enough to true them up. I don't think I'd gain much by switching to 113's, at least not enough to warrant spending any money.

 

Digging the car, have fun with her! Strongly considering grabbing my 3rd T/A TPI car very soon. Need more garage please.