361 truck engine

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May 25, 2004 | 08:56 PM

idealtrucks

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Fleet Mechanic

Joined: Jul 2002

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From: S/W Virginia

361 truck engine

what are the specs ona 1974 4bbl 361. its out of a big f750 truck. are they interchangable with a standard 360, or are they totally different. i just need a little information on them.

May 25, 2004 | 09:07 PM

Randyb12

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From: Eureka, Ca.

They differ in that they have steel cranks with larger snout. and the Distribitor uses a larger shaft. Some of the blocks will take a 4.13" bore.

May 25, 2004 | 11:00 PM

rusty70f100

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From: Iowa

The steel cranks are nice for racing, after you get 'em balanced, as they're externally balanced. Very strong crank. The heads have small ports and valves. The blocks are stronger than the standard FE block, with stronger alloy metal, and additional main support. They also have thick cylinder walls. They have low compression dish pistons, and big combustion chambers, like around 80cc. The distributor hole is bigger than the standard FE, but you can use a standard distributor with a bushing. They also have a larger oil pump drive shaft, so if you replace the oil pump with an FE oil pump you have to get an FE distributor.

Hope this helps!

May 26, 2004 | 05:00 PM

idealtrucks

Thread Starter

Fleet Mechanic

Joined: Jul 2002

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From: S/W Virginia

it sounds like that block is just made to be a lot tougher. i have an old 390 4bbl that i am planning on rebuilding. could i take this block and crank and put my 390 rods and pistons, heads and intake on it and just have the advantage of having a steel crank and extra main bearing or is it different or is the crank for a 390 or 391 bigger? am i making any sense?

another quick question also. this truck has the big 5speed still in it. what is the ratio's on this transmission and is is something worth getting to put in my f100, or is it just made for the big trucks?

Last edited by idealtrucks; May 26, 2004 at 05:03 PM.

May 26, 2004 | 08:31 PM

rusty70f100

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From: Iowa

The 361 has a 3.5" stroke, and the 390 has a 3.784" stroke. You could put the 390 crank and rods in the FT block, though. Use the original 390 heads, and get that distributor bushing I mentioned earlier.

For a normal build either block will work just fine. If you're pushing a lot of nitrous through it, or running high amounts of boost, the FT block might help. Otherwise either will work just fine. As for the crank, that 390 crank will take pretty much anything you can throw at it. The FT steel cranks will just take more than that.

May 26, 2004 | 08:52 PM

dinosaurfan

Cargo Master

Joined: Aug 2000

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From: SW Michigan

blocks, cranks, trannies

Ideal, the fordged steel crank is stronger, but the extra strength is not worth having with the extra weight if you only have the 3.5 stroke of the 361. And even if you had the 391 crank, you have to do a little bit of work to the snout. I'll look around and see if I can find the part number to the bushing that you''' need for the dizzy. But let's talk about that transmission. I'll bet you have a 280 series Clark 5 spd. You lucky guy. And you have the flywheel and clutch and starter and bell housing, right ? You'll need all that stuff to put it into the F100. You'll have to rebalance the flywheel ( easy ) and you might want to lighten it some, it weighs about 45 lbs ( 20 -25 works well in a pickup.) Are there any numbers on the tranny or in the big trucks cab ? My Clark 285 has 6.99 1st, 4.09 2nd, 2.35 3rd, 1.47 4th and 1 to 1 fifth. At least I think so, memory fades. I think it will be excellent in your F100. You might want to get some taller rear gears or tires. Even if you had 2.47 axle gears and 35 inch tall tires, the 6.99 first gear will get you away from stop signs quickly.

DF, @ his Dad's

May 31, 2004 | 09:01 AM

idealtrucks

Thread Starter

Fleet Mechanic

Joined: Jul 2002

Posts: 1,297

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From: S/W Virginia

that sounds like a pretty nice transmisison. ill try to get a number off the cab or something so you can teel for sure. would i have to make anyspecial kind of linkage to make it work in a standard cab where it came out of a cab-over?