440 piston/head combos

[jenkins71]

Hi guys. I got my 440 block back, and am having another "what would you do?" question.

The block was honed and check out. I am now at .030" over and ready to start building. The question is, what pistons and heads do I use?

I gave the machinist the L2266's (flat-top) that came inside the motor, as well as a set of used L2295's (domed, hi-comp) that I picked up for cheap. He checked the clearance of the piston sets to the wall, and they were as follows:
L2266: .003
L2295: .007

Both are within spec, but the 2295's are possibly a little on the loose side.

I want a good compression ratio, which is why I got the L2295's to replace the flat pistons. I have a set of good 452 heads ready to go, but they have big 96cc chambers and would have a really low CR unless I used the L2295's.

So, considering...

Should I re-use the L2266's and swap the 452's out for a set of closed-chambered heads? There is a set of 915's near me for $600. Assuming they have 78cc chambers, I would have a CR of 9.05:1 using the composite gaskets I have. If I switched to a steel shim gasket, I could get 9.5:1.

OR, do I continue with the plan and run the L2295's with my 452's? This would cost me another $200-300 as I would have to get the pistons balanced to my crank. This would end me with about 10.5:1 compression ratio.

This motor is for use in a 71 Charger. I want to build it for torque and mid-range power. I want as much power as I can get, for the least amount of money. Occasional trips to the drag strip, but mostly a daily driver powerhouse.

Thanks for your advice!

 

[Garys1969RR]

I would use the dome pistons with the 915 heads, for maximum power output. I have built 3 motors with this arrangement, (2-413s and a 451) . They produced awesome power! And the C/R calculator says that with .053" deck clearance, .020 gasket, 78cc heads, 12.1 piston dome is going to get you right at 11.9 to 1 C/R. And with variables such as space between the top ring and chamfer at the top of the bore, you may be closer to 11.5 to 1. Of course you will need to use hi octane fuel with this arrangement.

 

[jenkins71]

I would use the dome pistons with the 915 heads, for maximum power output. I have built 3 motors with this arrangement, (2-413s and a 451) . They produced awesome power! And the C/R calculator says that with .053" deck clearance, .020 gasket, 78cc heads, 12.1 piston dome is going to get you right at 11.9 to 1 C/R. And with variables such as space between the top ring and chamfer at the top of the bore, you may be closer to 11.5 to 1. Of course you will need to use hi octane fuel with this arrangement.

Thanks--- I was under the impression that with iron heads, you are best to stay at 10:1 or below?

 

[jenkins71]

any other input? I'm eager to start assembling this motor, but want to make sure I am doing everything right.

 

[Cranky]

For a street engine, 10-1 to 10.5-1 is pretty easy. Thing is, your pistons go from one extreme to the other. The 66's will make maybe 8-1 or so with a steel shim gasket and open chamber heads. Need to find a calculator and do the math. The 95's will make around 11+ with comp gaskets and open chamber heads. If you are not experienced with domed pistons on the street, don't use them but I would try and find a set of pistons that are better than the 66's for a healthy street engine even tho you can make one run decent with them. Just easier imo to go with pistons that's closer to 10 and not closer to 11-1 compression for a street engine.

 

[jenkins71]

If you are not experienced with domed pistons on the street, don't use them

Thanks for the advice, but what do you mean by that?
I appreciate any help! This is my first build and I'm really stressin these details. I want to put this thing together!

 

[Meep-Meep]

First of all I'd CC everything before you make a decision because what you might find as an actual compression ratio vs. calculated will surprise you. If you end up with 9 - 9.5:1 I'd say that's a winner. 915 heads are great and if you get 9.5-ish CR with a flat top that's the best combo.

 

[jenkins71]

Thanks for the clear pick man! I'm gonna mock up everything with the flat-tops once i get my bearings in the mail. Then I can double check my piston-to-deck clearance and do my calculations once again.

 

[Garys1969RR]

Hey Jenkins, just wondering what you finally settled on as far as a piston and head combo goes? Do you have it all together now? How is it running? Thanks!

 

[dieseldazzle]

Mill the Pistons and use the 915s