440 build 516's vs 915's

[moparfanUSA]

Well, I'm getting ready to buy the parts for the 440 that was given to me. Its a 1976 from a truck that has not been bored yet, so we are going to go 30 over. Going to buy sealed power flat tops. I have 516 heads, where as everyone keeps taking about 915 heads. I had the 516's on my other 440 while I was rebuilding the 906's and the engine had a lot more power, but it also ran hotter ( I think I had the carb running to lean, went up on the jet size and it seemed to help). So if everyone keeps talking about 915's, what am I missing buy using 516's.
I know they were used in the 64-67 year range for 316, 383, 413 and 426 wedge.
I have not decided on a cam yet or an intake yet. I was going to keep it somewhat stock , but I have slowly graduated to building something with some more power.
It will be a 4 speed car for the street. I plan on putting a Holly 850 DP on it.
So far I am leaning towards 440 source H beam rods, although Eagle in the Summit catalog has some nice ones.
I will not have the CR until everything gets measured for a better idea on what to do, but hope to soon.
So anyone have any reason NOT to use the 516's?

 

[IQ52]

You're missing 399. So there is no reason NOT to go up the 399 to the 915 from the 516 without more information. Like, what heads do you have available to you now. What is their condition and how much money is in the budget for heads.

"some more power" is relative. Stock but reconditioned 915 vs 516, the 915 should give you "some more power". Bigger valves in the 516's and some mild porting will give "some more power" than the reconditioned 915 heads. On and on ad infinitum.

 

[Bigal75]

Those Trick Flows look like nice heads..save up for something like that.

 

[Cranky]

You know all the piston suppliers have the compression height of their pistons and that will tell you where they will sit in the bore. Easy to figure what your compression ratio will be with any given head before buying slugs.....

 

[Meep-Meep]

The 915's have a better intake port but for a hot street car you are not likely to notice any difference between the two. If your 516's are available and in good shape vs. having to find a set of 915's then I'd use the 516's.

 

[Mike Gaines]

Rods for you .... the best deal for a mild build (less than 550HP) would be the 440 Source BRAND NEW FORGED FACTORY REPLACEMENT RODS. They are only $250 for a set of 8 and would be more than adequate for you build.
You will definitely want a "dual plane" intake (not a single plane)...try the Edelbrock for about $235 from Summit. 850 carb would be plenty. You want to consider how much you will spend on your iron heads to get them usable. 440 Aluminum heads (complete) are only $499 each. Just buy your cam and lifters and pushrods and you got your valve train handled. Stick to 10-1 (max) with iron heads and up to 11-1 (max) with aluminum heads so you can run pump gas.
Good Luck

 

[moparfanUSA]

Thanks, In guess I should have said that the 516's that I have were purchased with a complete value job, Harden seats, 4 angle valve job, complete rework, but no porting ect.....so they were done by a professional machine shop when I got them last year.

 

[Banzaiii67]

Thanks, In guess I should have said that the 516's that I have were purchased with a complete value job, Harden seats, 4 angle valve job, complete rework, but no porting ect.....so they were done by a professional machine shop when I got them last year.

They sound solid. You already have money into the 516s. What size valves are in them? If they didn't put in 1.74 exhaust valves. I would look into doing that and you could have them ported at the same time.

 

[moparfanUSA]

The 516's have a 1.60 exh valves in them now. I might take them to a shop and have them put in a 1.74 ( like the 915's and 906's). This way it would be more like the 906's but way less money,
Since the heads were all done professionally no reason to go out and find another set of heads.
I have been looking into what cam I want and so far I'm leaning towards an Isky cam. Their "264 Mega cam" 264 deg in and 214 exh. with 108 center. The valve life is only 4.50, bit it should be fine. They say this cam is good for between 9-10.5 comp ratio. Now I have to find rods and pistons. My engine builder wants to use "floating" wrist pins with locks in the ends, but I have not found any flat top pistons like that unless I have them made ( all of them have valve reliefs). The sealed power ones are press fit, but since I am not racing it I see nothing wrong with using the press fit ones, I just have to convince him of that.
I have to find out if I use a dual plane intake will the hood close with an air cleaner on it vs. a stock intake. Once the block is been bored I can start putting things together to see how far down in the hole they sit.
BTW, I made a mistake the engine is a 73 or 74 not a 76, but no big deal.

 

[Meep-Meep]

Sounds good regarding the heads and no reason to float the pins.

The Isky cam will work well too assuming you want to spend a lot of time with your foot to the floor. I ran the 280 Mega cam back in the 80's in my 383 and it screamed. The 108 LSA will lope and you won't have much vacuum but in the upper mid range it will run. In my experience this cam likes a single plane intake like a Torker but a Performer RPM might do as well or better. Since this is not a racer I'd like to talk you into a cam with a 110 or 112 LSA. Check the specs on the hemi grind (MoPar .474" / 280) or see if Isky will grind you that cam you picked out on a 112 LSA.

 

[moparfanUSA]

Thanks Meep! I looked at the Mopar performance. I think the one you described is the "280/280" Advertised "238/238 at .050 lift with a 110 sep.
So much different that the Isky "264. Isky does not have anything in their catalog with 110 deg except what the say ( quoting) "Best overall cam for towing, trucks, Vans RV ect. Broad Torque band Good Vac. 9.5:1 comp ration smooth idle" That one is 256 deg/262 adv 202/208 at .050 lift. 110 lobe.
The one I THOUGHT was good says " Tremendous Torque & good mid range power 9- 10.1 comp good idle, stock converter ( I have a 4 speed) 3.23- 3.70 alex ratio ( I have 3:55) up to 625 CFM carb )odd)

 

[Meep-Meep]

The Isky you picked will make great upper mid range torque for sure but with the higher overlap it won't be so low RPM friendly. You will have to alter the carb power valve or metering rod springs to deal with the mixture in a low vacuum environment.