5.9 Magnum log manifold tube size??

[nocar]

Im starting on a TT 5.9 build using 2 Garrets and intercoolers from 2 88 Daytona Shelby-Z T2 cars. Planning 1.5" weld ell 90* bends into a log with turbos mounted toward the front of the motor. 1.5" tubing is actually about 1.6 ID and I need to know what size log to use. Im thinking 2.5" but that seems big compared to the t3 flange and the ID of a factory cast iron manifold. It will be EFI with a 5 speed in a 74 D100. Any thoughts??

[nocar]

42 views and NOBODYS got an opinion?

[90TurboVan]

I'd measure the perimeter of the inside of the flange and select a tube size that will match it. With a turbo manifold, you just want maximum flow and heat retention. Twin Garrett's may be a little small for a 5.9. I've got two of them on my 2.5... The T3 flange is also not the right bolt pattern for a Chrysler turbo, but gives you many more turbo options. People have drilled Chrysler flanges for the T3 pattern and had the option of using either style turbo.

Sounds like a fun project, always wanted to TT a V8.

[mwinkle353]

You'll be fine making a simple log manifold out of 1.5" schedule 40 mild steel fittings or Schedule 10 Stainless Steel fittings.

If you want a high flow turbo setup, then do not go with the simple log setup. But for a simple starting point, you can't go wrong.