8BA stroker kit

3twinridges

3twinridges

Well-known member
Machine shop called me this am to tell me the 4” crank I brought them was cracked on a main journal. Time for a stroker kit.

This is a stock engine, stock carb/ignition. How big of a stroke can I go with? I want to go with at least 4 1/8 stroke but would to go 4.25 if possible, thoughts?

JB
 
4” crank on the way. I just didn’t like having to bore this good block out to 3 5/16 for the 4 1/8 and 4 1/4 stroke. 4” is plenty

JB
 
Just an FYI. you don’t need to bore block just because you install a 4 1/8” or 4 1/4” crankshaft. Either would have been a great addition and additional c.i.
 
KiWinUS said:
Just an FYI. you don’t need to bore block just because you install a 4 1/8” or 4 1/4” crankshaft. Either would have been a great addition and additional c.i.
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I was wondering the same. I think because the stroker kits usually come with pistons, rods, etc. as part of the "kit".
 
If anyone knows of affordable (same price or very close to 4" stroke) cast pistons for +0.060 or smaller overbore and a 4 1/8" stroke please let me know.
All the available 4 1/8" and 4 1/4" stroke pistons I find these days are +0.125 or larger over bore and many are forged. Unless building a hot rod engine these don't make sense to me. Given piston availability the 4" stroke crank makes sense to me.
 
38 coupe said:
If anyone knows of affordable (same price or very close to 4" stroke) cast pistons for +0.060 or smaller overbore and a 4 1/8" stroke please let me know.
All the available 4 1/8" and 4 1/4" stroke pistons I find these days are +0.125 or larger over bore and many are forged. Unless building a hot rod engine these don't make sense to me. Given piston availability the 4" stroke crank makes sense to me.
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38 Coupe,

Have you called Egge? I'm pretty sure they'll do any size. Ross will as well, but I'd assume they would be out of your budget range judging by what you said in your post.
 
When I talked to H&H yesterday it seemed like a 4.125 stoke was not in the cards without a 5/16 bore. But I see a 4.125 scat with standard size rod journals and Ross makes a 4.125 stroke 60 over piston so not sure why that combo will not work with standard rods. I am going to call H&H this morning and dig around a little more.

JB
 
3twinridges said:
When I talked to H&H yesterday it seemed like a 4.125 stoke was not in the cards without a 5/16 bore. But I see a 4.125 scat with standard size rod journals and Ross makes a 4.125 stroke 60 over piston so not sure why that combo will not work with standard rods. I am going to call H&H this morning and dig around a little more.

JB
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This went from being a stock build to a stroker motor real quick and I love it! LOL!
 
I would not build an 8BA without a 3 5/16 bore. I have done 3 of them and the machinist said they all would have gone more. ("OL' Ron" has mentioned 3 7/16"+ engines). To be fair, I did have to have one cylinder sleeved because of a casting flaw that caused a pit in the wall. The machinist said we could run it as is, but a sleeve would be good insurance.

The pistons cost about the same and like they say, "There is no replacement for displacement".
 
tubman said:
I would not build an 8BA without a 3 5/16 bore. I have done 3 of them and the machinist said they all would have gone more. ("OL' Ron" has mentioned 3 7/16"+ engines). To be fair, I did have to have one cylinder sleeved because of a casting flaw that caused a pit in the wall. The machinist said we could run it as is, but a sleeve would be good insurance.

The pistons cost about the same and like they say, "There is no replacement for displacement".
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Exactly!
 
The problem with the 4.125 crank is the lead time on 4.125 60 over pistons. Well over 4 weeks to have them built. 4” 60 over are much more readily available.

JB
 
Gosh, I remember when I bought a complete 296 stroker kit with floating rod bearings and Jahn's pistons from Crankshaft Co. in CA in 1967 for about $500. Then it cost me a whopping $5 per hole to have it bored. My pay back then was $1.15 per hour. Took a lot of "saving up".
 
3twinridges , I sent you a email or pm , I forgot what I clicked on . Its about a motor I have that I’ll not be needing now . It sounds exactly like the one you want to build .
Gary
 
I am going stay with the 4”. Machine shop talked me out of a 4 1/8. They were afraid the extra stroke would put strain on the bearing caps and introduce more wear than a 4” for not much gain.
 
Ggmac said:
3twinridges , I sent you a email or pm , I forgot what I clicked on . Its about a motor I have that I’ll not be needing now . It sounds exactly like the one you want to build .
Gary
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Appreciate it but the purpose of the build is to introduce the kids to an iconic engine build. I want them to see one get put together and help me. Again appreciate the offer. Follow along as we have fun with it!

JB
 
3twinridges said:
I am going stay with the 4”. Machine shop talked me out of a 4 1/8. They were afraid the extra stroke would put strain on the bearing caps and introduce more wear than a 4” for not much gain.
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For what you are looking to do, makes sense.

While you are in there, may I suggest cleaning up the exhaust and intake ports?

You can do this with sand paper rolls and a long arbor. The little effort/time it would take, it would make a difference and it will sound a little more like a hot rod flathead if you can get it to breathe better in & out.
 
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