Technical 307 with 400 crank

anyone build one?
wondering why ?
How might it run?
Well There’s one sitting here now.
I’ll probably open it up later this week to see what they did.

 

It’s basically a 283 bore with a 3-3/4” stroke. Small bore long stroke. More of a class engine for racing where a cubic inch requirement governs the total CID. What you have there is a 350. Long way around to get there.

 

I read in an old "Hot Rod", about one of these being built. Maybe late '50's early '60's. .060 over 283 with a 3.75 stroke. 364 cubes. Was in a dragster, don't know what it ran, just remember thinking it was really fast. Of course, it did have a blower on it. Gene.

 

Sounds like something for a Street Stock type roundy-rounder class requiring stock valve sizes, iron heads n intake etc. Folks would spend a lot blowing abrasives through heads n manifolds, and that long stroke would let it pull on the little carb a long time. Used to be fun to watch the Chebbelles and Torinos banging fenders, running on narrow recapped "class" tires on white spoke wheels

 

Longer stroke would have more torque for getting off the corners, this from a drag racer but the bore makes power?

 

Someone posted that article here a while back. Wild stuff from back in the day.

 

Where did the 3.75" crank come from, I wonder?

 

If old, weld journals and or offset grind.

 

I was just basing off the fact that he said it was a 400 crank. If so, those are externally balanced.

 

Ya, I was thinking he was basing the question on before the 400 cranks were available.
Anyways, be neat to see what’s inside the topic engine.

 

400 aka 383 Chevy crank in a big journal small block isn't an issue you just have to follow standard procedure.
The big issue might be pistons. Those might get expensive in comparison to what we know as standard stroke your 350 with a 400 crank pistons.
Still to go to that added expense and work a guy would have to have a specific reason to do it. Fits a certain association's class or possibly a low speed torque motor for offroad or other purposes.

 

Regardless... I wanna see pictures....

 

Me too! I did a search for 364 inch Chevy and didn't find anything.

 

With a std bore it works out to 353.

 

I remember that someone made a 400 crank stroker kit for the 305 block. Supposed to have nearly as much torque as a 350 with not much more gas as a 305.

Gary

 

There was a thread some time ago about overbored 283 and custom made cranks back in the late 50's, early 60's. I think they made 352 cubic inches.

 

364.8393 @ .060 over in a 283. I really don't remember if the article was about the engine or the dragster. It was quite some time ago that I read it. It was in a group of old magazines I got from my uncle. Gene.

 

This one? https://www.jalopyjournal.com/forum/threads/what-about-a-352-chevy.955620/

 

https://www.jalopyjournal.com/forum/threads/the-ellusive-352-sbc.257728/
according to this, the boss man here has had a couple
A 307 with 400 crank is mentioned

 

That combination also could have been inspired by a desire to use up a stack of random parts sitting in a garage floor.

 

I’ve seen that happen but it takes custom pistons- pretty sure anyway

 

Bigger bore lets you run bigger valves- but if your class requires stock valve sizes, long stroke will let you pull on them longer- just a different way to get the charge

 

There has to be something else at play, other than stroke length. At any given RPM a stroke is going to take a set linear time to be completed. The longer the stroke, the faster the piston has to move to complete it. Does this create a stronger vacuum? Does the longer stroke allow a later closing of the intake valve or an earlier opening?

 

A 283 with 4” bore and 3-1/2” crank was a 352”. GM made the 3.48 crank. A crank builder would never do it. Howard Johanson was building 352’s as soon as he could along with his aluminum heads in 1957. It was considered a “big” Chevrolet then.

 

I use these variable stroke rods.
Makes a huge difference

 

Too funny!....

 

More dwell at TDC creates the torque....

 

i really need a set of those rods . anyone making them for a 235 ? but seriously. gota be easier to go to the casino or buy lottery tickets . return is more likely ?

 

No offense intended Jimmy, but a 283 bore with a 3.50” stroke is 330 cid.

 

Can you elaborate on this?

Longer stroke is what produces more torque, it’s a longer lever. Now more cylinder pressure will certainly do that as well. Is that the thought behind the longer tdc dwell? More time to build pressure?