65 c10 LS3/4l80e swap with factory tunnel

[64509chvl]

Hey I’ve got the factory tunnel in my 65 & I’m curious if the LS3/4l80e fits without modifying the tunnel? I did a quick search & come accross a thread that says yes with certain cross members & motor mounts & some saying you need the high hump tunnel, but I’m pretty sure the high hump tunnel is only necessary with the 6l80? Thanks for any info! I have a Porter built front end coming with their front crossmember.

[1965Project]

This is the same combo I am getting together for my 65 as well. I'm almost to the point of being able to mock it all up but sure hope someone has the answer before I do. What mounts are you running?

[64509chvl]

Right on brutha! I went with a Porter built frond cross member with their front & rear suspension with coilovers. Their cross member slightly girdle up & forward. I don’t have it all yet, just trying to see what others have done with the tunnel for the 4l80 so I can get a jump on that now. I’m just going to fab my own tunnel to be safe, it’s easy enough!

[SCOTI]

Originally Posted by 64509chvl

Right on brutha! I went with a Porter built frond cross member with their front & rear suspension with coilovers. Their cross member slightly girdle up & forward. I don’t have it all yet, just trying to see what others have done with the tunnel for the 4l80 so I can get a jump on that now. I’m just going to fab my own tunnel to be safe, it’s easy enough!

You'll want a high-hump tunnel to clear w/the PB (or just about any raised x-member suspension). The 700r4 bellhousing is super tight on my PB/sbc/3° driveline angle combo. It cleared but had a fingertip (or less) gap w/the low-hump floor. I swapped to a modified high-hump tunnel & issue solved.

A greater driveline angle can also help with clearances. But that can also possibly create driveline related angle issues downstream.

[64509chvl]

Originally Posted by SCOTI

You'll want a high-hump tunnel to clear w/the PB (or just about any raised x-member suspension). The 700r4 bellhousing is super tight on my PB/sbc/3° driveline angle combo. It cleared but had a fingertip (or less) gap w/the low-hump floor. I swapped to a modified high-hump tunnel & issue solved.

A greater driveline angle can also help with clearances. But that can also possibly create driveline related angle issues downstream.

Very cool, appreciate the input. I’ll definitely just plan on building my own tunnel then. Thanks again!!👊🏻