Guess my 273 hp

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The 308 heads valves just barley clear the stock bore. I think I may turn them down on the lathe since I'll be doing a valve job anyways. One thing I noticed is the 308 heads valve springs seem real short compared to the springs on the 920 heads.
 
ProStocker273 said:
The 308 heads valves just barley clear the stock bore. I think I may turn them down on the lathe since I'll be doing a valve job anyways. One thing I noticed is the 308 heads valve springs seem real short compared to the springs on the 920 heads.
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?????? Turn them down? Are you talking about the valves? You notch the block to gain clearance and not turn down the valves.
 
I'm not pulling apart my bottom end to notch the block. Turning down the intake valve .02-.04 is just like running a smaller valve. Will not hurt anything as long as valve and seat are cut.
 
ProStocker273 said:
I'm not pulling apart my bottom end to notch the block. Turning down the intake valve .02-.04 is just like running a smaller valve. Will not hurt anything as long as valve and seat are cut.
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Better think that one over.....If you cut the valve it gets smaller.....if you machine the seat the hole gets bigger.
 
The valves clear just fine as is but I'll be going to a bigger cam and just want too be safe at full valve lift as the valves don't open perfectly vertically. Chevy sb have a 1.84 valve that would work but I can throw them in the cnc lathe at work and save a few bucks. Not too many people want to spend money on a 273, me included. I do want to see what hp and how fast I can get one though!
 
I'm cutting seat so I can sit the seat and the valve where I want. .02-40 is not a huge amount. We have a seat grinder and machine for cutting valves in are shop. Edit: sorry I meant overall so .01-.020 a side. There is more than enough material under the valve for this.
 
ProStocker273 said:
The valves clear just fine as is but I'll be going to a bigger cam and just want too be safe at full valve lift as the valves don't open perfectly vertically. Chevy sb have a 1.84 valve that would work but I can throw them in the cnc lathe at work and save a few bucks. Not too many people want to spend money on a 273, me included. I do want to see what hp and how fast I can get one though!
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Better check the valve stem diameter of those Chevy valves. There's a good chance they are smaller than the Mopar guides.
 
I'm not using chevy valves just made reference to them as a option to turning the ones I got but I am not running them. Either way I would not put a set of heads together with out new guides.
 
Well I had my 308 heads tanked and they are cracked between every valve. I talked to my machinist and he say they can braze the small crack on my 920 heads. So it looks like my 920 heads are gonna get some more love. 1.6 exhaust valves, spring pockets cut for dual valve springs and milled to bring compression up then put back on with .028 head gasket with 3.7 bore instead of the .40x 4.03 that's in there.
 
wasn't a stock 273 rated depending on year, 180 hp to 230 hp, so where the hell are some of these clowns coming up with 200 hp, im sure its running better then that
 
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