440-increasing compression with stocl pistons?

[polkat]

Well, I wanted to build this 1971 non-HP 440 for quench, but having no budget (to speak of) I've realized I simply can't afford the pistons I want. The present pistons are about .065" in the hole and the heads are 346's. What's the best approach to raising compression? The options I see are milling the heads and perhaps camshaft selection.

How much can the heads be milled safely, and what compression to aim for before reaching detonation with 92 gas?

What have you folks done? Thanks!

 

[Meep-Meep]

The easy way would be to use the 67 440 heads (2780915) or the earlier 516's and a steel shim gasket. That combo can get you nearly one point.

 

[Meep-Meep]

By the way, you're only a few hours from the bay area and I have several sets of 915 casting cores. I can sell you a set for $100.00 guaranteed no cracks. I have a magnafluxer at my shop. Most of the ones I have are the 1.6" exh valve and will most likely need guides. PM me if interested.

 

[66 coronet]

polkat. I hate to hijack your thread but i'm in the same boat. I have a low mileage 72, 413 motorhome engine that i was hoping to use with the stock pistons and drop on a set of the 516 heads i have but if this combo will only add i point of compression its not worth the trouble. My motors manual gives the 72 motorhome engine 7.5 compression stock if the 516 heads will only give me i point i'll need some pistons. I have the 65, 413 pistons from the engine the heads came from but at least two of them i would rather not use. Anyone have a couple of good 413 pistons they want to get rid of?

 

[Meep-Meep]

polkat. I hate to hijack your thread but i'm in the same boat. I have a low mileage 72, 413 motorhome engine that i was hoping to use with the stock pistons and drop on a set of the 516 heads i have but if this combo will only add i point of compression its not worth the trouble. My motors manual gives the 72 motorhome engine 7.5 compression stock if the 516 heads will only give me i point i'll need some pistons. I have the 65, 413 pistons from the engine the heads came from but at least two of them i would rather not use. Anyone have a couple of good 413 pistons they want to get rid of?

It all depends what you want to do. If you have the parts available to get a point of compression take it. Then get a cam that is specifically designed for low CR. The end result will be a good running engine in the low and mid range and will be happy with 87 octane - and not cost a lot of money. Shoot for about 160 PSI of cranking pressure. If you want to make power in the upper mid to high RPM range then you are going to have to spend some money on pistons and get a cam with some more overlap.

 

[67Dart]

Mill .030 or so off the block and the intake, then get shorter pushrods. That should get you in the ballpark.

 

[1968_Roadrunner]

I would zero deck the block. (the intake may still work as is) I have seen 440's that did. But like 67 Dart said, you will need shorter push rods. Good luck!

 

[340Arrow]

If you don't want to spend the money on push rods you can always shim the rocker shafts.

 

[polkat]

Thanks for all the responses guys. Unfortunately, I was wrong in that these are the non-HP stock pistons, which are .153" in the hole. Way too much to deck off the block. So I guess I'll be looking for the six pack type pistons anyway. If anyone hears of some for sale, let me know.

 

[chignikred]

DO not ever deck a 440 block. rarely do you ever need to , to clean up deck. You just screw up the block, spend needless money and perpetually make a mess of any intake installation alignment. If we are dealing with a stock bore , even - .007, some 'early' stock pistons will work fine. imho people are too picky about a loose piston fit anyhow. Change the heads to earlier heads, spec the cam. First off quit thinking all these $200 deals on 1977 440 engines are such a deal.
Alright off my soapbox.

fyi I also have a set of 67 HP 915's new guides ,seats, fresh valves, I can sell.

Also should have some early 10:1 413 std pistons

red

 

[1968_Roadrunner]

DO not ever deck a 440 block. rarely do you ever need to , to clean up deck. You just screw up the block, spend needless money and perpetually make a mess of any intake installation alignment. If we are dealing with a stock bore , even - .007, some 'early' stock pistons will work fine. imho people are too picky about a loose piston fit anyhow. Change the heads to earlier heads, spec the cam. First off quit thinking all these $200 deals on 1977 440 engines are such a deal.
Alright off my soapbox.

fyi I also have a set of 67 HP 915's new guides ,seats, fresh valves, I can sell.

Also should have some early 10:1 413 std pistons

red

Really? Most of what I have read about building B & RB engines say first off to zero deck the block. One to get the compression up and two for ideal quench. I am no expert engine builder...just repeating what I have heard.

 

[polkat]

Yea, I've never heard that either. Even the Mopar bulletins say to square deck the block. And this is not a 1977 $200 block. I see no problem with it.

 

[Cranky]

I check em for square before doing any machine work but will deck if it's not within .005. Yeah, you can play games with piston and rod combination to account for it being out a little bit but if I need to deck to get rid of a .015 piston in the hole situation, I will and sometimes you don't have a choice. I have a small block 340 that really NEEDS it because of neglect but I just don't understand why you say it screws up a block. I can understand not doing it if it doesn't need it....but....how does it screw it up? Lousy machinist?

 

[1968_Roadrunner]

My brother has a set of Speed Pro Forged 6 pack pistons for sale. Part # ZL2355F30. These are .30 over and have stock LY rods still on them. 1 rod is bent and the crank was bad so he went to a stroker kit. The pistons still all look like new. Very low miles on them. He wants $100 + actual shipping for the whole set with rods. PM me if interested.

 

[1968_Roadrunner]

Here are they are at Summit:

http://www.summitracing.com/parts/TRW-L2355F30/

 

[1968_Roadrunner]

Sent you a PM Cranky. Pending sale on the pistons.

 

[Cranky]

Back at ya....

 

[69 Runner]

........................

 

[polkat]

pistons

69 Runner, as the post starter I'm sorry I didn't get back to this before. I'm also interested in your pistons, so if Cranky doesn't get them, I'm interested as well. Sent you a PM!

 

[Cranky]

Go for em polkat....I'm working on a couple of engines for others and haven't heard anything back from one of them and I have another set pending....