Trying to determine engine for stroker
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Trying to determine engine for stroker
When I bought the truck I was told it's a 390 with 428 heads. Stock bore would be 4.05. My bore is 4.12. That's .070 over a 390 and .010 under a 428. I have never seen pistons .070 over. Is this normal? I pulled the engine because the bearings were shot. The crank seems to be aftermarket and is .030 under on the mains and .020 on the rods. Rods are from a '63 @ 6.488, heads '66 C6AE-R, other parts '68 and the block '67...C7ME-A. I never measured the stroke.
I want to do a stroker. I will have to go to a 4.13 or 4.16 bore with this block for a stroker correct?
I want to do a stroker. I will have to go to a 4.13 or 4.16 bore with this block for a stroker correct?
Laughing Gas
Joined: Mar 2007
Posts: 754
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From: southwest Wisconsin
Many 390 blocks won't go .060 over, few will go .080. Only way to know for sure how far you can go is to have the cylinder walls sonic tested for thickness.
If you want to know about strokers I suggest contacting Barry at Survival Motorsports.
If you want to know about strokers I suggest contacting Barry at Survival Motorsports.
Posting Guru
Joined: Jul 2003
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You can also use a 428 crank (3.98 stroke). Things to think about are final compression ratio. If you are using your truck for a daily driver, you might want to get aftermarket pistons to bring down the compression ratio to 9:1 so you can use regular fuel. That would make a great truck engine. Years ago, I built one for our old 73 F250 and was going up a grade pulling our old 30 ft. 5th wheel, and a guy in a Chevy with 454 badges on the side, went past me pulling his 5th wheel, with a big smile and waved as he went by. I down shifted to third, put the pedal to the floor, and as I went by him I waved, and he had this look on his face.....
That alone was worth the time and money building that engine.
That alone was worth the time and money building that engine.
More Turbo
Joined: Nov 2007
Posts: 703
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From: Western Washington
LOL...I know what you mean Maxtor about building a strong solid engine. People look at my truck and think it's old and slow till I put my foot into it and see the look on their face change.
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Joined: Feb 2006
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To the best of my knowledge there are no 4.120 bore FE production pistons.
You are gonna have to recheck that bore & find out what you really have on your hands. Take a good look at the pistons you removed - they very often have an indication number stamped into them.
The crank can be identified by casting numbers on the counterweights - look for a 1U, 1UA, 1UB - you done good. Far more likely is a normal 390 or 360 cranks. If you're building a stroker you'll throw it aside or sell it anyways...
The cheapest big cube stroker will use a Silvolite cast piston, a BBC pressed pin I beam rod, and a cast Scat 4.250 crank. You can pin hone the .975 pin FE pistons to take a larger .990 Chev pin. Problem is that you're only saving +/-400 bucks versus the forged piston package, and you need to press in the pins - shop labor.
You are gonna have to recheck that bore & find out what you really have on your hands. Take a good look at the pistons you removed - they very often have an indication number stamped into them.
The crank can be identified by casting numbers on the counterweights - look for a 1U, 1UA, 1UB - you done good. Far more likely is a normal 390 or 360 cranks. If you're building a stroker you'll throw it aside or sell it anyways...
The cheapest big cube stroker will use a Silvolite cast piston, a BBC pressed pin I beam rod, and a cast Scat 4.250 crank. You can pin hone the .975 pin FE pistons to take a larger .990 Chev pin. Problem is that you're only saving +/-400 bucks versus the forged piston package, and you need to press in the pins - shop labor.
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I will have to check the bore and pistons again even though I've triple checked already becasue of the odd size I was getting. I just need to take it to someone to tell me if it is usable.
For those of you with strokers what heads do you have? I have C6AE-R heads. I talked to a shop and he wants to put $1100 of labor into the heads and put 2.09 and 1.65ish valves in it. For that price I would just buy aluminum heads.
For those of you with strokers what heads do you have? I have C6AE-R heads. I talked to a shop and he wants to put $1100 of labor into the heads and put 2.09 and 1.65ish valves in it. For that price I would just buy aluminum heads.
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Needsmorecoffee.
Joined: Oct 2004
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From: CT
Also double check the crank you have. If it is aftermarket like you said it already might be a 428 or larger stroke crank. Scat stuff has been out long enough that you now see some used stuff out there. But if it's a Ford crank you should see some ID numbers on the edge of one of the counterweights. There are a few of the more common ones to find.
2T, 2TA is 3.50" stroke
2U, 2UA or 3U is 3.78" stroke
1U, 1UB or 1UA is a 3.98" stroke.
Those are cast iron OEM Ford cranks. There are quite a few more so see what you can find if anything. Forged Ford cranks commonly have a $ symbol on them with a casting/part number. Cast iron cranks have a pretty sharp parting line running down them. Easy to spot. Forged cranks have a smoother wider line that's not as noticable.
Your better off buying new heads as for $1100 into your old ones you just about there. Or if you can find a nice set of used heads already worked on that's another option. But before you start spending check out what you have as you might be able to use some things. You can also sell your old heads and things to recoupe some cash.
2T, 2TA is 3.50" stroke
2U, 2UA or 3U is 3.78" stroke
1U, 1UB or 1UA is a 3.98" stroke.
Those are cast iron OEM Ford cranks. There are quite a few more so see what you can find if anything. Forged Ford cranks commonly have a $ symbol on them with a casting/part number. Cast iron cranks have a pretty sharp parting line running down them. Easy to spot. Forged cranks have a smoother wider line that's not as noticable.
Your better off buying new heads as for $1100 into your old ones you just about there. Or if you can find a nice set of used heads already worked on that's another option. But before you start spending check out what you have as you might be able to use some things. You can also sell your old heads and things to recoupe some cash.
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Found a nice surprise...I measured to stroke and got 4.0 and found a 1U on the crank so it must be a 3.98 stroke. I'm still getting 4.12 for the bore. The pistons measure 4.087 in diameter. The underside of the pistons have a 5 digit number but I can't read any of them. 238-99 would be my guess. There is also a cow or bull head cast above the number.
I guess the crank is worth keeping, still not sure about the block.
I guess the crank is worth keeping, still not sure about the block.
Senior User
Joined: Feb 2006
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Cool on the crank. Nice find.
Pistons sound like they could be Federal-Mogul/Sealed Power parts.
If you can pull one out you'll find the basic part number normally cast on the side by the piston pin - won't show oversize though. Where are you measuring the piston? If its on the mid of the skirt you probably have a .040 over 390 block - 4.090 bore would give .003 clearance - believable measurements...
Pistons sound like they could be Federal-Mogul/Sealed Power parts.
If you can pull one out you'll find the basic part number normally cast on the side by the piston pin - won't show oversize though. Where are you measuring the piston? If its on the mid of the skirt you probably have a .040 over 390 block - 4.090 bore would give .003 clearance - believable measurements...
Senior User
Joined: Feb 2006
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Yep - sounds like you have a 428 there. Next question is whether it's a "real" 428 or a way overbored 390. Pop out the center freeze plug and look at teh bottom of the water jacket between the center cylinders. Most 428s say "428" down there. Also look for a crude "C" or "A" scratched into the bellhousing area. Looking like a good find so far!