TPI in disguise
Thread Starter
Burning Brakes
Joined: Nov 2004
Posts: 800
Likes: 3
From: Port Orange FL
TPI in disguise
I know this has been done before but I thought I would post it here as I dont recall seeing it talked about on this forum, at least recently. Following are pics of my TPI motor in disguise. I took an edelbrock intake and spent hours working it over on both ends enlarging the most restrictive areas. Then I took a sit of SLP runners and did the same thing. I shortened the length on the runners to about 4.25 inches by siamesing them at the top. I took extra time to reduce the bumps where the bolts go as far as possible and enlarge the cross sectional area around them. Its just under 1.75" as deep inside the runners as I can measure. Its a real PITA trying to get all the way thru these but it can be done. Both the runners and the intake now have an average cross sectional area of over 1 5/8" and almost 1.75". This makes them larger in diameter than basically anything you can buy except for the first manifold, and gives a similar runner length as a superram has. As best as I can measure I am going to end up with a total runner length of just over 10 inches and an average diameter of almost 1.75" versus 13.5" and 1.5" in a stocker. Hopefully this is going to extend my RPM enough to make me smile when I wind her up..... 
Melting Slicks
Joined: Aug 2003
Posts: 3,403
Likes: 398
From: Lakeville MI
I've previously done similar porting to the upper part of a set of SLP runners and used them with a stock base. I didn't enlarge the remainining runner diameters since it didn't make much sense to do for my plans to use the stock base
In my car the power peak ocurred at 4800 rpm, and didn't drop off sharply until 5400 rpm or so. It dropped maybe 20 HP between 4800 and 5400, with a big drop around 5500 rpm.
I think you should make good useable power to 5400-5500 rpm, which would make for a suitable shift point. Any higher rpm would likely result in less HP than what you will have available in the next gear, depending upon the actual gear ratios. I didn't notice which trans you have.
In my car the power peak ocurred at 4800 rpm, and didn't drop off sharply until 5400 rpm or so. It dropped maybe 20 HP between 4800 and 5400, with a big drop around 5500 rpm.
I think you should make good useable power to 5400-5500 rpm, which would make for a suitable shift point. Any higher rpm would likely result in less HP than what you will have available in the next gear, depending upon the actual gear ratios. I didn't notice which trans you have.
