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Discussion Starter #1 (Edited)
Hey guys my brother is looking to possibly build up a low mileage 1987 H.O 5.0 motor in place of his tired old 302....I have never built and have very limited experience with the 5.0 engines....I see horror pictures all the time on the net of broken cranks and split blocks..What do these engines need addressed to live at 350-400 hp and lets say 6000-6500 rpms?

Or is he better off rebuilding his older non roller block?
His current engine is a 1978 block with factory flat top pistons but the rods have been resized with ARP bolts.
We were thinking he could just throw his top end onto the 5.0 block but don't want to grenade it if its not up to some abuse in stock form.
 

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Hey guys my brother is looking to possibly build up a low mileage 5.0 motor in place of his tired old 302....I have never built and have very limited experience with the 5.0 engines....I see horror pictures all the time on the net of broken cranks and split blocks..What do these engines need addressed to live at 350-400 hp and lets say 6000-6500 rpms?

Or is he better off rebuilding his older non roller block?
His current engine is a 1978 block with factory flat top pistons but the rods have been resized with ARP bolts.
We were thinking he could just throw his top end onto the 5.0 block but don't want to grenade it if its not up to some abuse in stock form.
use a early 28oz crank . cut down rear oil slinger . plus need correct damper and flywheel . zero imbalance is best , that 50oz is part of the problem of blocks/cranks breaking . then build it like any sb
 

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What do these engines need addressed to live at 350-400 hp and lets say 6000-6500 rpms?

Or is he better off rebuilding his older non roller block?
Either short block is fine for that target. Ford conservatively rates the 5.0L roller block for 400 hp and 6000 rpm. You can push them considerably more for HP with a precision build and sharp tune. He doesn't need to do anything to it, however, I would always recommend blueprinting everything to both ensure reliability and to get those extra ponies.

The 5.0 has a bit of an edge for pistons and rings, but pick your compression height carefully, and deck the block to suit with the proper RMS finish for the chosen gaskets. Same C8 rods right up to the Explorer, so he can use his resized rods too. Use ARP main cap bolts or studs also. The cheap roller cam option is obviously an advantage.

As you know, actual 400 hp NA from a 302/5.0L does not come with just slapping parts together. Tell him to just do the job right, pick parts that work together and tune it well, and he will be happy - with either one.

David
 

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I see horror pictures all the time on the net of broken cranks and split blocks..What do these engines need addressed to live at 350-400 hp and lets say 6000-6500 rpms?

Or is he better off rebuilding his older non roller block?
His current engine is a 1978 block with factory flat top pistons but the rods have been resized with ARP bolts.
We were thinking he could just throw his top end onto the 5.0 block but don't want to grenade it if its not up to some abuse in stock form.
Those split blocks you see of grenaded blocks are NOT from 350-400hp, those are the ones that are USUALLY in the 600+ range and LOTS of boost/N2O....

That said, not knowing WHAT his top end consists of, thats a hard call.... MHO.
 

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Discussion Starter #6
Well if we used the low mileage 5.0 the attraction was that it didn't need any work to the shortblock assembly..Just swap on his top end and maybe a new roller cam......It kinda defeats the purpose of using it if we have to redo the bottom end...

He does have another 1987 engine from a van that is a roller block but not equipped with a roller cam...It is a high miler in need of rebuilding..Perhaps we should use the crank and rods from his 78 motor and swap into the roller block?..

Or option#3 :D
This probably won't happen but if he does a stroker 347 is it really worth it to stay with the older non roller blocks?
 

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Discussion Starter #7
Those split blocks you see of grenaded blocks are NOT from 350-400hp, those are the ones that are USUALLY in the 600+ range and LOTS of boost/N2O....

That said, not knowing WHAT his top end consists of, thats a hard call.... MHO.
His top end is fairly mild..
1965 289 heads ported with bigger valves
Old school twisted torker manifold with 600 cfm holley carb
I am not sure of his cam specs but something like a 270H grind..
Long tube headers..
The intake and camshaft are suspect items that may be changed in the build as well..Obviously the camshaft if he uses the roller block.
 

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Those split blocks you see of grenaded blocks are NOT from 350-400hp, those are the ones that are USUALLY in the 600+ range and LOTS of boost/N2O....

That said, not knowing WHAT his top end consists of, thats a hard call.... MHO.
what about the stock hp 50oz blocks that take out 1 & 2 mains ?
keep them slow rev'ing and under 5500 rpm , no problem
 

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what about the stock hp 50oz blocks that take out 1 & 2 mains ?
keep them slow rev'ing and under 5500 rpm , no problem

I am not here to try and prove/disapprove the destruction of stock block bottom ends, I was just giving MHO on the carnage he was talking about he had seen online, and if you do some research the split blocks arent from 350-400hp. That is all I was saying.... But now that you bring that 1 & 2 mains being taken out that might be another discussion about the 351W firing order that has been brought up in another thread.....
 

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I am not here to try and prove/disapprove the destruction of stock block bottom ends, I was just giving MHO on the carnage he was talking about he had seen online, and if you do some research the split blocks arent from 350-400hp. That is all I was saying.... But now that you bring that 1 & 2 mains being taken out that might be another discussion about the 351W firing order that has been brought up in another thread.....
not taking about 351W's

I posted what comes into the shop .

take or leave the info . not my engine , always up to the owner
 

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Well if we used the low mileage 5.0 the attraction was that it didn't need any work to the shortblock assembly..Just swap on his top end and maybe a new roller cam......It kinda defeats the purpose of using it if we have to redo the bottom end...
With the top-end parts listed, he will have zero issues with a stock 5.0 short block. He also won't hit 400 hp - but that's a different discussion. The Ford rating is with the 50 ounce crank. Fart is correct that the failures you see online are primarily bleeding-edge engines, and most saw pre-ignition initiate the failure. Extensive failure analysis shows the real-life strong and weak points of any combination, and the 5.0L short block at 400 isn't it. The '78 block has no advantage for a 347 either. BTW, that same failure analysis combined with computerized stress analysis (FEA) would change your mind about zero vs 28 vs 50 ounce balancing in the rpm range used with this combo. That's how they're making 500-600 hp on stock 5.0 short blocks; you have to know where they break and why. Go for it.

David

A forged, knife-edged, very expensive pro-racing crank. Notice any thing funny? Like, where the largest masses of weight are? And are not? Why is that? Oh, never mind - this isn't an FEA thread. ;) For what your bro is doing, any of the short block assemblies will serve:

 

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Discussion Starter #12
Yes I know he won't hit 400hp with those parts but wanted a bit of a safety factor built in just in case..
 

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With the top-end parts listed, he will have zero issues with a stock 5.0 short block. He also won't hit 400 hp - but that's a different discussion. The Ford rating is with the 50 ounce crank. Fart is correct that the failures you see online are primarily bleeding-edge engines, and most saw pre-ignition initiate the failure. Extensive failure analysis shows the real-life strong and weak points of any combination, and the 5.0L short block at 400 isn't it. The '78 block has no advantage for a 347 either. BTW, that same failure analysis combined with computerized stress analysis (FEA) would change your mind about zero vs 28 vs 50 ounce balancing in the rpm range used with this combo. That's how they're making 500-600 hp on stock 5.0 short blocks; you have to know where they break and why. Go for it.

David

A forged, knife-edged, very expensive pro-racing crank. Notice any thing funny? Like, where the largest masses of weight are? And are not? Why is that? Oh, never mind - this isn't an FEA thread. ;) For what your bro is doing, any of the short block assemblies will serve:
you ever look inside a crank case ? lets say you have ... how would you fit a wider couterweight at the #2 & 4 mains ?

what was the results of a 50oz crank at 8000 rpm ? the test rpm lower where external balance difference come into play ?
 

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Yes I know he won't hit 400hp with those parts but wanted a bit of a safety factor built in just in case..
this going to be carb or efi ?
carb , I'd get a rpm type intake , swap to the steel dist. gear , advance the stock roller cam . thats for the low mileage 87HO he'd have more power than before . few other parts would need changing and some mods made
 

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Discussion Starter #15
this going to be carb or efi ?
carb , I'd get a rpm type intake , swap to the steel dist. gear , advance the stock roller cam . thats for the low mileage 87HO he'd have more power than before . few other parts would need changing and some mods made
It will be carbed..He is talking about switching to an edelbrock air gap intake and reusing his built 289 heads which are fairly fresh..
He is worried about the stock rod bolts in the 5.0 when spinning it up to 6000 rpms...
 

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It will be carbed..He is talking about switching to an edelbrock air gap intake and reusing his built 289 heads which are fairly fresh..
He is worried about the stock rod bolts in the 5.0 when spinning it up to 6000 rpms...
6k on stock bolts is ok

what is the 5.0 going in ?
 

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Discussion Starter #17
The motor will be going in a 67 mustang, t-5 with 4:11 rear..It is primarily a street car but will see the drag strip a couple times of year.....My understanding is the 5.0 has the same rods as his 1978 motor?...Everything I have read says the small stock rod bolts are a weak link in the older smallblocks...If this is true then wouldn't the 5.0 have the same issue or has there been an improvement in the bolts?
 

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For the cost why not put a set of ARP rod bolts in it? Seems silly to me to go through all the work and not upgrade the easy and relatively cheap parts, stock bottom end 5.0 will handle 6k, hell how many flogged 5.0 mustangs are out there with 100k miles on them??
 

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On a side note let me know how that T-5 and 4:11 gears do you, I have a T-5 and 3:70 gears because I was afraid 1st gear would be worthless with a low gear
 

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Discussion Starter #20 (Edited)
On a side note let me know how that T-5 and 4:11 gears do you, I have a T-5 and 3:70 gears because I was afraid 1st gear would be worthless with a low gear
It is my brother's car but I know he loves the T5 and 4:11s..I am not sure about first gear but on the highway it runs exactly the same as his old 4 speed toploader and 3:1 rear....My brother had a drag pack cobra jet car back in the day with 4.30s in it so he does not "fear the gear". :D
 
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