Another head inquiry...

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Yeah, that was one of the things I learned the hard way when I was younger. One set (I think they were 346s) I did I gasket matched the exh, then worked the SSR a bit, and it flowed 170ish and sounded horrid as I recall. I did a bit more studying and some other sets of heads and the last set I did went 190 at .550 and is much smaller overall than the "maxxed out" earlier sets.
 
txstang84 said:
I haven't finalized my decision on pistons yet. With what research I have done so far, that'll be a pretty big expenditure...probably Diamond flat tops. And if I calculated it correctly, I should have about the same CR as what you mentioned. I didn't plan on running a relief-less piston because I didn't figure I'd be able to get away with much more than stock lift, let alone if I want to run as close to zero deck as possible.

Thanks for all your input-what cam are you running anyway? I'm only posing possibilities as of right now...I just really want to run a roller cam and many of them have pretty high lift compared to their flat tappet cousins, so I already figured on running some pricey pistons...
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Sorry I didn't respond earlier. I am running the ElCheapo Summit .465" hydraulic grind. I figure with the stock rockers crappy ratio, it might make .450" lift, yet my mph indicates around 400 HP. I intend to swap in the .528" MP solid which I have on the shelf. Another member has the exact same valve size as me, same pistons, same piston to deck measurement, and runs the .509 MP hydraulic. The .528 MP grind reportedly has more clearance than the .509 grind.

If you are only looking for around 400 HP, I think you could skip the big dollar pistons and roller grind. One of the magazines made 460 HP with 9.2 comp and a flat tappet Comp cams grind, with stock cylinder heads.
 
BBBCUDA said:
What pistons do you have? If they are stock style flat tops with no valve reliefs, I don't think you will fit a .540" cam. I have 516's with 2.08"/1.74" valves, and I don't have room for that big of a cam. My pistons sit at .020" in the hole. With the bigger valves, (nail head type), and a light mill, I was able to get 9.97/1 compression with a .039" head gasket. Thats hard to do with an open chamber head. According to my best Mph at the track, my 383 is making a little over 400 HP, and it has a much smaller cam than you are looking at. Good luck.
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Why did you use a .039 gasket with pistons .020 in the hole ?

If you are only looking for around 400 HP, I think you could skip the big dollar pistons and roller grind. One of the magazines made 460 HP with 9.2 comp and a flat tappet Comp cams grind, with stock cylinder heads.
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I get a kick out of people quoting that 383 build as the benchmark when it's a known fact the dyno it was run on was very HAPPY during that time frame.

Would have been nice to see it put in a car and run down the track to see what HP it was REALLY making .

On those 516's I'd put 1.74s in it and see if you can salvage the exh ports with them before getting to carried away with the bigger valve. if you put the 2.14 intake it would be a good idea to notch the top of the bore to unshroud the valve , same on the exh side , 426 Max Wedges were notched on the exh side with the 1.81 , or was it 1.88 ?? ... exh valve size ... same bore as the 383 ...
 
If the heads you have aren't salvageable on the exhaust port I've got a set off a 400 in storage, (casting #4006452). I'm down in SA, they are yours for the taking, could probably meet you part of the way if it would help. They're just taking up space right now.
 
Thanks for all the replies fellas-I greatly appreciate it. I guess I'm still on the fence As to whether I'll run 2.08/1.74 or 2.14/1.81. Either way I'll be getting new valves, and I already found a set of adjustable rockers that came with springs and retainers (thanks physixx).

I think the valve size for the max wedges was 1.88 on the exh side-I don't plan on using any *that* big :). I'm much more concerned about being able to use the heads.

Oh-notenoughcash-thanks for the offer. I'll certainly keep it in mind if the heads turn out to be door stops-thanks again guys!
 
OK, so I found a set of 915s on feebay...they should be on my porch in about a week :cheers:

As mentioned in previous posts with my 516s, I still intend to open up the bowls for bigger valves. I haven't checked the pricing on it yet, but I'd also like to have hardened seats installed and a 3 angle valve job plus back cutting the new valves...

I found a cam I liked in the classifieds here...Crane hyd roller 284/292 total...222/230 @ 050...509/528 lift on a 112 lsa. I also picked up a set of adjustable ductile rockers and some springs from the classifieds too! yay! Progress is slow as molasses sometimes, but I do still have occasion to get some parts and play around here and there. As unfortunate as it is, I'll probably have to send my engine outta town for machining since most places around here [that I trust] are back-logged for months.

If you guys have some suggestions on setup for these heads, I'm all ears...If I do any porting on them, it'll probably be just bowl work or basic port cleanup-nothing extensive as I don't really want to turn them into a boat anchor. Thanks again y'all...
 
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