Flathead rebuild

Theholygrehl

Theholygrehl

Member
Hey guys im rebuilding my flathead 1947 block.Using the original crank, and everything else is new. Bored .30 over isky race cam, offy heads, off reg duel cab intake and 2 stromberg 97 carbs. Couple questions what should my carbs be jetted at, or what's a good place to start? Also what hp do you think I will be at when I'm all done?

Thanks.
 
Here are some pictures before I painted
 

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You should get a copy of JWL's book. He has a bunch of Dyno tests on engines such as yours. As far as HP is concerned, probably around a 100-120 at best. Remember these engines only produce about 80, originally. Should make a nice street engine.
 
Ya Im going to try stock first, I wasn't sure if I need to use smaller jets on the back carb, I'm sure the front carb will be my primary
 
You really don't want to run a progressive linkage - so both will run in unison, there is no 'primary' carb. You'll want to jet them both the same --> .045 on the mains with a .069 power valve (stock stuff). Be careful on fuel pressure, these carbs just don't like any more than 2 to 2.5 lbs. All the modern 'repop' fuel pumps put out more than that - so either change the spring in the pump to an old/used one - or get a high quality low-pressure regulator.

Best of luck - you'll have fun with your engine!
B&S
 
Great thanks, I was going to use my original fuel pump 70 years old and was still working fine when I pulled it. Will it pump enough fuel for two carbs?
 
The original pump should be fine, it is the internal diaphragm that will be the issue. Modern fuel and original rubber parts do not mix.
 
My avatar roadster has similar carburation (I have a super dual) and after reading the plugs went down to .043 jets and 67 pv to get them light brown instead of black.
 
You'll most likely have to have the offset bracket. I think you can use the 49 and later water pumps and crank pulley to push the alternator out a bit to clear that front carb. I'm not sure if that is doable though.
 
My alt is in the middle with my Edelbrock Super Duel. I have an old one with the stud there for a mount. The newer versions don't have that, just tapers down. I think there are pictures of it in my public album of my 32 roadster.
 
Theholygrehl said:
Hey guys im rebuilding my flathead 1947 block.Using the original crank, and everything else is new. Bored .30 over isky race cam, offy heads, off reg duel cab intake and 2 stromberg 97 carbs. Couple questions what should my carbs be jetted at, or what's a good place to start? Also what hp do you think I will be at when I'm all done?

Thanks.
Click to expand...

If you have a offy regular dual a generator or alternator should fit. Not with a super dual.

John
 
My memory isn't so good! I made the bracket and did off set the alt slightly. Car has been on the road since 2001 so that was 15 years ago . Not exactly in the middle.
 
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