Center/Front/Rear Mount Adapter

[bgott]

Pulled my motor last weekend and started looking at the TBI to square bore adapter I ordered from trans-dapt and what less than impressed. Would require removing material from the intake for a smooth transition and I am not keen on doing that to a brand new intake, especially if down the road I decide to change it out and sell it.

So, given my career in rapid prototyping and CNC milling capabilities at my job, I started to design my own with smooth transitions to the width of the square bore intake.

In my design I got to thinking what is the benefit of TBI positioning on the intake. I don't want to starve any cylinders relative to one another so I would assume that center plates or slightly forward mount would be best for that? Currently I am setup in a forward mount spot even with the front of the intake port. I've seen other people design these on here and wanted to see if anything stands out as being better.

This is what I've got so far.

[Fast355]

If I can remember to snap some pictures I have a square bore to 2" bore Marine TBI adapter off a 405 HP Mercruiser 502. It is approximately 2" tall, and has a tapper all the way from the top of the 2" bore to the spread bore oval flanges.

[bgott]

If I can remember to snap some pictures I have a square bore to 2" bore Marine TBI adapter off a 405 HP Mercruiser 502. It is approximately 2" tall, and has a tapper all the way from the top of the 2" bore to the spread bore oval flanges.

Fast I assume this is a center mount setup?

My spacer is designed to be .75" minimize the height of the breather when it's all together. Don't think I will run into hood clearance issues with a full size truck, but don't want to make it gargantuan either.

[dave w]

Pics are "D Shaped / Port Volume Matched" square bore TBI adapter plate. Send me a PM for the STEP file. Original file is .pkg format.

TBI_Adapter_SquareBore_Port_Matched_01.jpg

TBI_Adapter_SquareBore_Port_Matched_02.jpg



dave w

[bgott]

Cut this out, based off of dave w. design last night. 6061 Aluminum.

Fits my performer RPM nicely. I didn't bother to do clearance work from the bottom side, so it isn't truly "port matched" in my case, but I think will work nicely for me. Still need to polish the tooling marks out of the bore taper, just didn't have time last night. IMG_1664.jpgIMG_1669.jpgIMG_1666.jpg

[dave w]

dave w

[Fast355]

Honestly I would not polish it and leave it slightly rough. I might even go so far as to take a small cuttoff wheel and a dremel and purposely carve ridges in it. The reason behind that is so it will help atomize any raw fuel droplets that might try to collect and run down the bore of the spacer. I often add the same grooves on the intake manifold ports for the last 2 inches of each. Liquid fuel does not burn, vapor burns.