Need honest opinions on a build

[Rebelrouser]

Here is what I am thinking about. Buy a 440 source 3.75 stroke crank, reuse the stock rods, .055 overbore with forged Icon FHR pistons, (for a Pontiac) . The cam, heads , and the rest of the drivetrain would remain the same. It would end up as a low deck 413. What do I gain? A little over 50 cubic inches, and a lot more low end torque. Is it worth it? Did I mention the factory A/C is a pain to work around?

Remember you will gain compression with the longer stroke, static compression is volume at TDC compared to BDC, so even if the piston is at same height because the piston in lower in the bore you will have mor compression. I strongly recommend getting a good engine program and play with your combination before spending money on parts. I like performance trends, but there are several others. You can get a lot more info than just HP and torque. cranking compression, idle vacuum, octane requirements, timing advance curve, etc. etc. And from experience, if you put good numbers in the program, it is dead on. I have my own dyno and it hits really close 99% of the time.
https://www.performancetrends.com/Engine-Simulation.htm

 

[qkcuda]

Thanks, but I have pretty much decided on a stock stroke build on the 400. Compression will be a bit under 9:1 to run on regular gas. Time will tell.

 

[qkcuda]

I got the rod and piston assemblies out today. The bearings had a little trash in them, but no scoring. The crank looked pretty good too, might even clean up with a polish. An interesting note was that there was a 7 on the deck pad and another 7 on the crank, so I expected that rod to be different, but all the rod bearings had the same markings, all dated 11 72, and all appeared to be standard? The crank spins freely, so hopefully the mains are as good.

 

[qkcuda]

I got the crank out today. The mains were .010 under from the factory. Again the bearings didn't look bad, so it didn't run long once the oil pump drive broke.

 

[Runcharger]

Always a good thing when you're the first one to go in after the factory.

 

[qkcuda]

For sure, and the factory didn't waste much. My 361 had a flaw in the valve pocket in the head they just ground out and the engine had a water test. This one had .010 under mains and it looks like perhaps oversized exhaust valve stems .

 

[qkcuda]

I did some more research, and it appears that I misread the info on the block pad. The E refers to a cast crank engine and the X with a maltese cross refers to .010 undersized main bearings, which checks out. That means the heads should be all standard sizes. The 7 stamped in the drivers side pad and on the crank throw is still a mystery to me.

 

[RemCharger]

The 400s I've seen usually have a number there. Not sure what it denotes, if anything
Here's 2 I have

 

[qkcuda]

Interesting, mine has the 7 there and also on the crank throws. There was nothing different about the number 7 rod or bearing that I could see.

 

[RemCharger]

Interesting, mine has the 7 there and also on the crank throws. There was nothing different about the number 7 rod or bearing that I could see.

View attachment 1549072

View attachment 1549079

One of the blocks still has a crank in it, I'll have to take a look