Things to do to truck while building 406? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Irishpilot · 03-12-2008, 07:19 AM

I'm building the 406 to have around 450ft/lbs of torque, but I'm pulling it out of my '71 that currently has the stock 307 mated to a turbo 350 tranny. I don't know what size gears are in the rear end, but I'm worried that the 200+ ft/lbs of gained torque is going to break stuff pretty quickly. So, here are the questions:

1) Do I need to replace the stock stall to a 2500?
2) What can the stock rear and a turbo 350 stand on the torque?
3) Any other things I need to consider before dropping the engine in?

redhead69 · 03-12-2008, 08:06 AM

Just did this swap and recommend getting a big block radiator (4 core) and shroud. I put a gm25 hughes converter and like it, good streetable converter but not necessary. Your stock tranny will be right on the edge of its limits but doable. If your planning on beating on it have it built up a little.

03-12-2008, 07:19 AM	#1
Irishpilot Registered User Join Date: Jul 2006 Location: Kunsan AB, South Korea Posts: 187	Things to do to truck while building 406? I'm building the 406 to have around 450ft/lbs of torque, but I'm pulling it out of my '71 that currently has the stock 307 mated to a turbo 350 tranny. I don't know what size gears are in the rear end, but I'm worried that the 200+ ft/lbs of gained torque is going to break stuff pretty quickly. So, here are the questions: 1) Do I need to replace the stock stall to a 2500? 2) What can the stock rear and a turbo 350 stand on the torque? 3) Any other things I need to consider before dropping the engine in? __________________ 1971 C-10, 406ci, restoration begun! 406ci sb; zero decked, bored .030, edelbrock aluminum e-tec heads, edelbrock performer RPM intake, comp 268 cam, comp 1.6 pro-magnum roller rockers, MSD street fire HEI, MSD 8.5mm wires, Holley Street demon 770, Hedman LT headers. 10.6:1 compression, Air Ride Tech bags on all 4-corners.

03-12-2008, 08:06 AM	#2
redhead69 fugedaboutit Join Date: Mar 2005 Location: Gresham, OR Posts: 832	Re: Things to do to truck while building 406? Just did this swap and recommend getting a big block radiator (4 core) and shroud. I put a gm25 hughes converter and like it, good streetable converter but not necessary. Your stock tranny will be right on the edge of its limits but doable. If your planning on beating on it have it built up a little. __________________ Currently truckless

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