Anyone else plan engine builds?

[qkcuda]

Years ago I built a high compression 400 by piecing together parts long before aftermarket pistons were readily available. Lately, since I bought the Charger, I have been working out a plan to build a stroker 361 to create a low block 413 torque monster. Turned down 440 crank, bushed stock rods, KB Olds 455 pistons. It all works on paper. I will probably never build it, but I have fun trying to work it out. Am I nuts, or does anyone else obsess over dumb stuff like that?

 

[747mopar]

Any time I'm planning on building a motor I do tons of research, weigh the options then put together an affordable plan and start parts shopping looking for bargains.. I enjoy the whole process.

 

[Big bill]

I'm working on a plan right now mostly factory parts but a few new old stock or should I say dead stock parts going for a period correct look and brute force and ignorance .

 

[qkcuda]

I had worked out a pretty nice combination to create a 413 out of my 361 block. It would use a 440 source 3.75 stroke crankshaft, stock rods, and KB pistons. I then started thinking about using a 400 block with the 361 crank and rods, and KB pistons. It would involve less machining, and the pistons weigh almost exactly the same as the stock ones. Both engines end up at exactly the same cubic inches and compression ratio, with quite different components. Here is the question, since everything is equal, what do you think the difference in output would be between the small bore long stroke and large bore short stroke combos?

 

[dodgedifferent2]

Working on piecing a 400 stroker motor together.

4.25 stroke crank
4.375 pistons for 10:1 compression
512 cubic inch
Indy ez-1 heads (bare)
Indy ez-1 intake 4150.
Solid roller camshaft not picked yet.

Planning to stuff into a 67 dart with a motor plate. T56 magnum and dana 60 with 4.10 gears. 28" tire.

 

[mopar 3 B]

I had worked out a pretty nice combination to create a 413 out of my 361 block. It would use a 440 source 3.75 stroke crankshaft, stock rods, and KB pistons. I then started thinking about using a 400 block with the 361 crank and rods, and KB pistons. It would involve less machining, and the pistons weigh almost exactly the same as the stock ones. Both engines end up at exactly the same cubic inches and compression ratio, with quite different components. Here is the question, since everything is equal, what do you think the difference in output would be between the small bore long stroke and large bore short stroke combos?

I will have to look into it, but I was not aware the 400 and 361 had different strokes. To my knowledge all BB blocks used a 3.38 stroke.

 

[qkcuda]

The 361 and 400 do have the same stroke. In order to get 413 cubes out of the 361 it requires a .060 overbore and a a 3.75 stroke crank. To get 413 cubes out of a 400 only requires a .060 overbore. My gut tells me the long stroke motor will make more torque, but would it be a significant difference compared to the cost?

 

[qkcuda]

No firearms? You gotta problem!

Working on piecing a 400 stroker motor together.

4.25 stroke crank
4.375 pistons for 10:1 compression
512 cubic inch
Indy ez-1 heads (bare)
Indy ez-1 intake 4150.
Solid roller camshaft not picked yet.

Planning to stuff into a 67 dart with a motor plate. T56 magnum and dana 60 with 4.10 gears. 28" tire.

That must use a shorter rod? I had a 400 based stroker with a 4.15 crank. I used 6.76 rods and the piston was very short.

 

[68 HEMI GTS]

I would never start any build using a 361 block. Right off the bat you’ve really limited yourself with valve size on the cylinder heads and bore shrouding due to the small bore. Yes I like to plan combo’s but I’m also willing to scrap ideas when they don’t make sense. So many readily available parts now a days it doesn’t make sense to get all out of the box. You’ll spend way more money to have less engine. Only time I would get really creative is for class specific type stuff.

 

[qkcuda]

You're right of course. When I built the first 400 I had to get creative, because there were no aftermarket pistons available. The only reason to consider using the 361 block is that is the original engine to the car. The 413 is also a nostalgic choice as we had a 413 in a 64 Chrysler. This is not a max performance build, it is mainly for torque to push a 400O pound car with 2.94 gears down the road

 

[Outsider]

I've been waiting for years to get back to this stuff; and now I'm retired and it's now or never. Put together a Dart with a crate 400 I bought new from Chrysler about 40 years ago that's been sitting in the corner.

Bought some KB pistons and added a little weight to the pistons to bring back closer to stock. First time I've tried to race a external balance motor and it seems to be holding up.

One of the quality checks I do is check overall balance. I have a Bently Nevada vibration monitor and was surprised that at 6.5k rpm the external balance 400 was actually a little lower vibration than the one of my higher dollar internal balanced motors at under 4 mils displacement.

So yes I plan motor builds, have a couple more I want to try, and consider it a luxury of this time in life

 

[qkcuda]

Looks like I have a line on a low mileage 400 block, so the 361 crank and rods in the 400 block scenario may happen. The stock 361 pistons weigh 717 grams, while the KB240 pistons are 690 grams at .030 over. So you end up with a forged crank, internally balanced, 400 with a 9.5:1 compression ratio.

 

[dodgedifferent2]

That must use a shorter rod? I had a 400 based stroker with a 4.15 crank. I used 6.76 rods and the piston was very short.

6.535 rod. Same piston as the 470. Oil ring not interfered with the pin.

 

[Cheapsunglasses]

I try to plan an engine build, then I look at my bank account, then I don’t plan an engine build

 

[qkcuda]

Planning is the operative word, that costs nothing more than my time. i think I will end up trading some parts for the new block. After that I will have to see what comes available for pistons. I can afford to wait.

 

[cj's mopar]

I built 400 block 440 crank 383 rods with 1.73 compression height piston I bought for a 493 .
Worked out nice with some sorce heads deck cut to 70 cc .
Compression around 10.5 to one or so can't remember.
But it runs great with a 228 236 525 roller cam and a six pack setup.

 

[Cheapsunglasses]

I built 400 block 440 crank 383 rods with 1.73 compression height piston I bought for a 493 .
Worked out nice with some sorce heads deck cut to 70 cc .
Compression around 10.5 to one or so can't remember.
But it runs great with a 228 236 525 roller cam and a six pack setup.

That sound like a killer combo!

 

[cj's mopar]

Still tuning but yea for what it is it's pretty good.

 

[qkcuda]

I built 400 block 440 crank 383 rods with 1.73 compression height piston I bought for a 493 .
Worked out nice with some sorce heads deck cut to 70 cc .
Compression around 10.5 to one or so can't remember.
But it runs great with a 228 236 525 roller cam and a six pack setup.

Yes the combo I had worked out for the 361 block was the same but with 1.75 compression height pistons. Because of the smaller bore, I could not use any Mopar pistons.