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440 Build advice

TexasRoadRunner68

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Looking at maybe doing a semi budget build on my 70 440 to get my car driving for the time being.

I have a 70 HP2 long block with the externally balanced six pack rods and the non recessed pistons. I’m guessing the 9.5:1 pistons.

Assuming I recondition the rods and have the block prepped, does anyone have any advise for lighter pistons that would bump the compression up? It seems many people just junk these due to the weight and rotating mass they ad.

I’d probably top it with a six pack intake and some aftermarket aluminum heads and a decent street cam. I would assume the block can handle the 500-600 hp that would likely be able to produce on the high end.
 
Really need to define your build purpose and budget. 440 six pack pistons are heavy compared to most aftermarket pistons. However, they are also about 9.5:1 CR with 906 heads. Those 6 pack rods could easily be replaced with some stock LY rods to reduce mass. If you change your rotating components you should have it balanced. 440'
 
Well on a semi budget I would run whats there. Put your money in the upper end.
 
IMO, if you want 500-600hp the pistons and rods should be changed to lighter aluminum. A few years ago I built a 500hp 440 and did that. They were cheaper than I thought at the time and the cost of prepping the old rods compared to new ones didn't make sense. If I had to do it again I'd replace the crankshaft to aluminum too. Even though that's not needed for my hp I would sleep better and never look back.
 
Six pack piston has 4 valve releifs, the other hp pistons are flat tops down the deck farther and lower compression.
I would suggest buying eagle rods or switch back to LY rods..there are acouple piston choices, we went with icon. Internally balance it then, you won't need a externally balanced convertor or damper.
 
Aluminum Crank ? Who makes that for 440?

May as well go full roller bearing, and of course consider a 3/4 race cam too. Go all in if you can find an HP3 block would be a nice start.
 
I’m curious what the cost would be with rods and pistons vs just doing a full stroker kit from 440 source. I also have a 400 that I could do a 470-512 build with. If it’s not too much more I may go that route and keep the 440 in case the car ever goes back to date/factory correct.
 
What heads?
If you looking for better compression the KB 237 is near zero deck and works on closed chamber heads. The KB 236 is the same piston with a raised pad to work with open chamber heads like the 906.

And I agree on the LY rods. Doing great in my 500+ hp build. My shop set them up for floating wrist pins and added an oiling hole. Also used ARP rod cap bolts.
 
What heads?
If you looking for better compression the KB 237 is near zero deck and works on closed chamber heads. The KB 236 is the same piston with a raised pad to work with open chamber heads like the 906.

And I agree on the LY rods. Doing great in my 500+ hp build. My shop set them up for floating wrist pins and added an oiling hole. Also used ARP rod cap bolts.
Did they bush the pin end? Or just hone them?
 
Looking at maybe doing a semi budget build on my 70 440 to get my car driving for the time being.

I have a 70 HP2 long block with the externally balanced six pack rods and the non recessed pistons. I’m guessing the 9.5:1 pistons.

Assuming I recondition the rods and have the block prepped, does anyone have any advise for lighter pistons that would bump the compression up? It seems many people just junk these due to the weight and rotating mass they ad.

I’d probably top it with a six pack intake and some aftermarket aluminum heads and a decent street cam. I would assume the block can handle the 500-600 hp that would likely be able to produce on the high end.

All depends on what you want to do with the car. Sounds like a streeter. For a streeter that stays at about 6000 RPM max, the heavy six paK rods are OK. The '70 pistons should be just fine with a small chamber aftermarket aluminum head and a moderate cam, check the piston to valve clearance with whatever cam you pick. If you stay with the big rods, use ARP bolts.
If you want lite, all it takes is cash and a really good machine shop.
 
One thing you may consider is if you are reusing the convertor on a externally balanced engine I would keep it externally balanced. If you are starting fresh then I would internally balance.
You are right on the stroker route. If you are buying rods and pistons, the difference is the price of the stroker crank minus the cost of turning yours(if it needs turned)
If you are going with Ly rods your looking at resizing and arp bolt costs. There is really no reason not to do pressed fit pins. Imo.. Full floating is nice, but optional. I would go w eagles before bushing a LY. LY rods can fail past 550hp. It's all fine until it let's go.
 
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