Does anyone think its worth the time and money to rework a set of j heads for a 455 ? I may be acquiring a 75 455 engine which has the j heads on it ,and I have another set in the garage . I would like to change out the pistons to increase the compression and maybe shoot for 400 hp without breaking the bank . Still not sure what I would put it in , but the price is right so it won’t hurt to sit on it for a while.if I get this motor I will start a thread on the build , will need plenty of suggestions.thanks

 

That would depend on what exactly you mean by "rework", I suppose. And of course the cost. I lucked into a set of reworked J heads for my build that were fully ported, polished, bowl work, AIR bumps gone, new seals, etc. And at a great price. BUT! After I installed them a bunch of C and G heads popped up for sale for not much more $ and they were reworked as well. If, like you say, you're not in a hurry, start the rest of the build and keep an eye out for better heads.
Just my experience.

 

Thanks Mac I will be on the lookout for some better heads .i put a set of e-heads on my 76 455 and made a big difference . And yes when I said reworked I meant the things you described I’ve read some of your thread on the 455 build and got curious about those j-heads.

 

If you are going to port the heads and install bigger valves, J heads are as good a starting point as any Olds head - arguably better because no one cares about them and they will be cheap. The reality is that for the same money, have Bernard Mondello provide a set of ProComps.

 

I knew someone would bring up the Mondello Procomps, lol. Joe, I would argue the phrase "for the same money". My rebuilt J's were a little more than a 1/4 of that price. Like I said, I think I got lucky.

Jeff, if you're looking at my thread, I hope it's because you want to learn from my mistakes.

 

Read my post again. I'm not talking about "rebuilt" J heads. I'm talking about having J heads ported and big valves installed so they actually make power. If you're going to spend that kind of money, you are far better off with aluminum.

 

I think what Mac meant was he found a set of already ported and freshly rebuilt J heads. Same thing for my rebuilt #6 heads, $400 for heads that had $1200 worth of parts and labour in them. The $1200 price which would be now $1500 and the same price as Procomp heads and still not as good.

 

Yeah, I'm never that lucky.

Of course, the OP was asking about a non-ported set that he has.

 

Yes the set I have are factory heads that would need bigger valves, seals , port , and bowl work, maybe a.i.r bumps removed . So it could get up there in price . Thanks to all you guys I appreciate the help

 

btw mac i would love to learn from your mistakes instead of mine for a change what are some of the things you would do differently ,looking back ?the engine looks great !

 

Sorry Joe, I should have been more specific. Yes, my heads had all the good stuff but alas, not the larger valves. Still a good deal though.

Jeff, ask me that question when I know if it runs, lol. But let me think; maybe a fancy new balancer before having the rotating assembly balanced (now I'm stuck with the original), a better oil pan (only because I didn't see how dinged up mine was until I painted it), maybe aftermarket rods (I had the stock rods rebuilt with ARP bolts and the caps were near impossible to get off. I had to buy a rod splitter!), uhhh, I guess that's it until I know more. I went slowww and tried to do everything right. I should have multiplied my cost estimate by a factor of 4 but the wife knows to do that for me, lol. Oh wait, yeah I know what I would do differently. I should have saved for a roller cam if for no other reason than to avoid the darn cam break-in. I hate that part!

 

Thanks 307. Seems you're always there to make sense out of my nonsense

And Jeff, the Facebook Oldsmobile buy, sell, and trade page has the occasional set of heads for sale. A couple of months back a fellow had a set of C heads complete with roller rockers for, I think, $800. About a thousand miles on them. So yeah, keep your eyes peeled.

 

 

Here's something I learned with the 455 I bought that was "rebuilt". If you pull a pushrod and black soot pours out of it, I would question the quality of the rebuild. At least, that's what happened to me. Luckily I didn't believe it when I bought it.

 

i agree on the cam break in .was on pins and needles when we put a new cam in my 76 .all went well though.the guy i got this motor from said "drove in the yard and pulled the motor "well it must have sounded like sh-t cause the bearings looked like hell in there !!scraped a pound of rust scale and dust out of the water jackets.

 

 

Yeah, Copper gave me a cam and a set of new lifters. It has what, 500 miles on it? I then had to buy the matching valve springs. When I was degree-ing the cam, I measured the lift. It was spot-on to spec. But a used cam with new lifters still has to be broken-in. The lobes need to be mated to the lifters.
I haven't gotten that far yet. Hoping for early May.