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First SBF build.. 347

2K views 9 replies 4 participants last post by  zildjian4life218 
#1 ·
Well I have had my hands inside on plenty of SBCs and now im ready to move into unfamiliar territory. I want to get a 302 to stroke into a 347. The kits seem cheap enough and I can do most of the machine work required myself which will keep costs down. Now I am looking at running factory GT40 heads that will most likely be ported by myself and a roller cam so I imagine a late model engine from an explorer would be the best candidate to start from. Now according to this site... http://www.stangnet.com/mustang-forums/threads/best-year-for-the-302-block.482448/
late model blocks came with forged internals from the factory. Is this true? Would you guys recommend me starting with a 302 from an exploder for this build. I figure that way I have the heads I want and provisions for a roller cam. I am looking for no more than 350-400hp from this engine. Any and all input is appreciated. Thanks!
 
#2 ·
zildjian4life218 said:
Now I am looking at running factory GT40 heads that will most likely be ported by myself and a roller cam so I imagine a late model engine from an explorer would be the best candidate to start from.
No, it wouldn't be the best to start with... The late 5.0s are nowhere near as strong as the 289/302 blocks from the late '60s

zildjian4life218 said:
Now according to this site... http://www.stangnet.com/mustang-forums/threads/best-year-for-the-302-block.482448/
late model blocks came with forged internals from the factory. Is this true? Would you guys recommend me starting with a 302 from an exploder for this build. I figure that way I have the heads I want and provisions for a roller cam. I am looking for no more than 350-400hp from this engine. Any and all input is appreciated. Thanks!
The forged internals of the '87-'93 aren't going to do you any good if you're stroking it, you're going to throw everything inside the block away. So why bother with a late model 5.0??

The only benefit for using the Exploder 5.0 is the roller ready block, and it ain't that much of a benefit...
 
#4 ·
Yes, a late model block will work, just remember that most of the issues with the 5.0 are in the bottom end, cracks forming from the main cap fastener holes, fretting on the block/main cap mating surfaces, improper assembly and so-so balancing will get you a pair of 4 cylinders with a common crank when pushed to the limit.

Also plan for new harmonic dampener and flywheel/flexplate, as the 347 kits are 28oz" imbalanced...
 
#6 ·
Personally I prefer starting with a 351W rather then the 302/5.0L for cubic inches - but regardless, either makes a good basis for a stroker engine. As far as strength - Mexican or Australian blocks have been probably the best, but I have never seen either one. Everything else for strength, well I have yet to see anything but an 'urban myth', no real world proof that early blocks are better. In fact, you can end up spending a bunch of extra bucks looking for bell housings or transmissions to attach to the back of many early 5 bolt bell circle blocks. Even the much vaunted early 351W with the so called high nickle content is a myth. A 351 with a .030 overbore is 355cid and more cubic inches then is reasonably priced and easily possible for a 302

While the 347cid based on a 302 gives you many more inches, you will be giving up some engine life and possibly having additional oil consumption with using such short pistons. First of all, piston rings are wrapped around the pin hole. Then you get into connecting rod ratios and piston scuff. IMHO, a much better 302/5.0 combo is the 331. This uses the same 5.4" rods, but has a 3.25 stroke rather then the 3.4 and keeps the rod ratio at a better approximate 1.7+ vs the 1.5 (I've forgotten the exact ratios). And a roller block - that opens up the door for many good camshafts without additional machine work plus eliminates the frightening break in of flat tappet cams wearing at initial start,

But, it's your engine, and your desires, we are just offering other alternatives to consider :D

Dave W
 
#7 ·
Irelands child said:
Personally I prefer starting with a 351W rather then the 302/5.0L for cubic inches - but regardless, either makes a good basis for a stroker engine. As far as strength - Mexican or Australian blocks have been probably the best, but I have never seen either one. Everything else for strength, well I have yet to see anything but an 'urban myth', no real world proof that early blocks are better. In fact, you can end up spending a bunch of extra bucks looking for bell housings or transmissions to attach to the back of many early 5 bolt bell circle blocks. Even the much vaunted early 351W with the so called high nickle content is a myth. A 351 with a .030 overbore is 355cid and more cubic inches then is reasonably priced and easily possible for a 302

While the 347cid based on a 302 gives you many more inches, you will be giving up some engine life and possibly having additional oil consumption with using such short pistons. First of all, piston rings are wrapped around the pin hole. Then you get into connecting rod ratios and piston scuff. IMHO, a much better 302/5.0 combo is the 331. This uses the same 5.4" rods, but has a 3.25 stroke rather then the 3.4 and keeps the rod ratio at a better approximate 1.7+ vs the 1.5 (I've forgotten the exact ratios). And a roller block - that opens up the door for many good camshafts without additional machine work plus eliminates the frightening break in of flat tappet cams wearing at initial start,

But, it's your engine, and your desires, we are just offering other alternatives to consider :D

Dave W
The only reason I was going to go the 302 route was they are easier to come across and are much more plentiful. and I could get a complete roller 302 with the heads i need for $100 at my local u-pull. And if I get a 302 out of say a late 90s exploder I have a better chance of getting a newer lower mileage motor as opposed to me getting a 20+ year old 302 or 351. Does anyone see any issues with me getting a 302 from a late 90s exploder? I gotta find the years that came with the GT40 heads so I know which one to pick.
 
#8 ·
zildjian4life218 said:
The only reason I was going to go the 302 route was they are easier to come across and are much more plentiful. and I could get a complete roller 302 with the heads i need for $100 at my local u-pull. And if I get a 302 out of say a late 90s exploder I have a better chance of getting a newer lower mileage motor as opposed to me getting a 20+ year old 302 or 351. Does anyone see any issues with me getting a 302 from a late 90s exploder? I gotta find the years that came with the GT40 heads so I know which one to pick.

There are really no issues with that roller cam motor. Just make sure that it has the heads you want on it.
 
#9 ·
zildjian4life218 said:
Does anyone see any issues with me getting a 302 from a late 90s exploder? I gotta find the years that came with the GT40 heads so I know which one to pick.
I think the last of the 5.0L Exploders and Mountaineers had the GT40 heads, so that would be 2000/2001. In my area, they're available for $450, check car-part.com for your are prices...
 
#10 ·
Canzus said:
I think the last of the 5.0L Exploders and Mountaineers had the GT40 heads, so that would be 2000/2001. In my area, they're available for $450, check car-part.com for your are prices...
wow thats crazy. My local u-pull its like $115 for an engine... I think they slap on some bs enviromental charge put i think its still under 150.
 
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