I've a stock 360 manual 4x2 in a 71 250 Sport Custom, I wanna make a swap to a 390 or to a 428, since all FE blocks are the same (352 ci) I believe I can work with my stock block to make it a 390 or 428 ci, but I wanna know if there is a really big difference between a 390 or 428 in terms of torque and horsepower, and what may I need to make possible this swap.

Thanks for any advice or info given

 

making your 360 a 390 is no problem.....all you need is a crank, pistons, and rods from a 390. the 428 would require being bored out .080 over (the bore on the 360/390/410 is 4.05 vs. the 438 at 4.13). and some blocks cannot be bored out that far, but if you do make sure and have it sonic tested. BUT you can make 410 with the 390 rods and piston, but with a 428 crank. the 390's make good torque (not sure on exact numbers) the 410's would make more torque and both would be excellent truck engines

 

yea you wont get 428 out of that block unless you had an FT motor that was sonic checked to make sure, so i would just stroke what ya got there isnt gonna be that much differance if you build it right.

 

the answer is yes, well sorta :-)

You can stroke your 360 to a 390 or a 410 safely. They have the same bore as the 360, just using a different crank to get a longer stroke.

360- 3.5"
390- 3.78"
410/428- 3.98"

you can also go aftermarket to get strokes up to 4.25".

You will see an improvement on torque with the longer strokes. And provided enough breathing room, more HP.

Check out the search feature. There are many threads on FE strokers in this forum!

I'm running a 428 stroker at 446 Cubes using an aftermarket 4.125" stroke crank.

 

if he has a mirror image 105 FE block its very likely it can take a .080 overbore, mine does, its been sonic tested, to ensure you will have no problems the most i would go is .060 over, it wouldnt be enough to tell the difference to take the chance with a .080 overbore.

 

Yeah, I think the best advice is to keep the block stock, with no overbore and just use different pistons and a new crank , but the question now is may I have trouble if i keep the 4 speed that came with the 360?

 

Oh i know fordman but most likely its not but your right.

 

i didnt mean to sound rude if i did, i just wanted to make sure he knew if he had that block he could have a chance at a .080 overbore. =)

 

i dont think you would have much trouble if you went with the 390, but if you went with a radical 428 i dought the 4 speed would hold up without some mods.

 

I know..........

 

can you use a 428 crank in a 390 block with the 390 pistons and 390 rods ?

 

i dont know about that matt, i think if you used 390 rods and pistons with a 428 crank it would be almost pushing the piston out the hole, i could be wrong though.

 

yeah i believe you can use a 428 crank in a 390.

 

You can use a 428 crank in a 390... its a 410.

 

yeah we all know that BUT can you use a 428 crank in a 390 block with 390 rods and pistons?