455 build, for 65 gto , new member
 

the 455 is a 73 with4x-1h heads, 114 cc, listed at 8 cr,
i want to get some cat iron heads that would increase cr
any recommendations?
i do have #13 set, #62 set, old 421 heads
the #62 heads seem to have most potential, not sure that the cr would be too much
1965 gto 389 tri power, auto, 355 gears
1965 gto currently a 400, 4 sp soon to have 455
paula

6X #4`s would be good on that engine as the 13`s or 62`s would need a dished piston to run on pump gas.

Are you looking to totally rebuild the engine, or just bolt on some different heads? As stated above ^ you'd need dished pistons to use the 13 or 62 heads and run pump gas.

How much power are you wanting?

I have a 455 with 114cc heads, pistons over 0.020" in the hole and 0.030" over CHEAP pistons (built by previous owner) with the beveled outer edge - so I'm under 8.0:1 cr. But with a cam I designed and a set of Tri-Y headers, it runs surprisingly well. With a stock torque converter and 3.08 gears, it will smoke the tires from idle (no powerbrakeing needed). And it runs on 87 octane with no problem at all.

horsepower to 400
i wanted to use 455 pistons, the cam bearings are shot, haven't got to mains as yet,
stock rods and a 068 cam, new rockers, etc
trying to be as cost conscious as possible
how about milling the 4x-1h heads down to increase cr?
thanks for response
paula

4X heads are to prone to cracking. The 6X-4s, even in their stock 92cc form, will raise your C/R to a decent level(9.3:1). I would use the 041 cam or an 041 clone with Rhodes lifters and the 1.65:1 rockers.

The 13 castings or the 62s are the only ones you should only be concidering out of what you have .

These two heads have close to the same chamber size and since the use of either casting will call for a dished piston I would go with the 13 casting since it's Exh port in stock form is better flowing then the 62.

look here, better performance cooler temps Twisted rear axles

http://forums.maxperformanceinc.com/...d.php?t=824649

eric
 

thanks for the offer, way out of my range at this point, but they r sweet
paula

Realistically the #13 and #62 heads you have are better. But, they will pretty much require a dished piston which adds expense. While some have done it, I was never able to get my #62 headed +.030 455 to run on anything less than 100 octane and I have the benefit of living 4500 ft above sea level.

If you're able to share what your approximate budget is, it would be helpful in providing better advise. If this is really a budget build and there isn't room for a dished piston upgrade, than talking about the #13's or #62's on this engine is probably the wrong direction.

If you have access to quality pump E85 and are willing to put the work into the fuel system to support that, the better #13 and #62 casting heads you have may end up working well.

Yep. Ran 62`s on my 455 for a few years. Broke 2 cast pistons. I`m close to sea level with hot summers. Detonation city. Went forged with av gas afterwards. Got tired of that and went with 6x4`s.

You could swap those desirable heads for some 6x4s. Those 13s and 62s are good 400 builds heads

Definitely agree. This is probably the best direction keeping with a strict budget. Get the compression up just a bit without spending much if anything extra.

I'm making assumptions that the heads the OP currently has are ready to go.

Some of you guys do not understand the concept of a STRICT budget. The 6X-4s will give the best “bang” for the bucks WITHOUT “breaking the bank” on forged dished pistons. Not every one enjoys hauling Avgas or racing gasoline around in 5 gal containers.

Even a set of the less expensive 6x-8 400 heads would be a good upgrade, normally somewhere around 101 to 105cc chamber volume. With a cleanup cut they'd put your compression at a nice 9:1 ratio, plenty of compression to add some pep and be able run whatever premium pump gas you might find and would tolerate regular in a pinch if premium isn't available.

The 068 cam could be used on such a combo. 6X heads are likely one of the most available Pontiac heads, in either the -8 or -4 version. They came with induction hardened seats and are great without any port work.

Precisely. The reason why I like the -4s is they start with a smaller chamber, reducing the milling needed to reduce the chamber size.

Agree. I have a set of station wagon ‘77 400 6x heads on my 455 and it’s 9.3 : 1, plus they’re screw in studs (aren’t 4x press ins ?)
The difference between this set up and the factory 29,000 mile stock 7.6 : 1 455 is night and day.

Lets be realistic here folks , I mean come on!!

Any cast iron Head the op uses will need to get rebuilt to one degree or another unless he is able to latch on to a all ready rebuilt( and at a great price ) 6X- 4 casting , a 5C-4 casting of something like a 1971 casting 96 casting.

The Block will likley need a rebore unless it's very low milage ,so right there the dished forged Pistons come into the picture and the compression issue of running his 62 or 13 heads becomes a moot point!

Eric one thing to keep in the forefront of your mind is that when your on budget and even more so when your dealing with the long stroke of a 455 its the smart thing to do to dump as much money as you can into the short block as in good Forged Pistons and Rods also if you can.

This way you can maybe run some crummy heads for a while , but not have to rip the block out of the car , just step up to better running heads when your wallet allows it .

Pontiac heads stand up to a lot of miles with little ware if they have had regular oil changes so one of your casting may just need new valve stem O rings and a .060" shim under each spring and they will be ok for you and the 068 Cam.

In fact I would not be surprised if you could get a easy 2 years out of them while you save up for getting a full rebuild done to the other set of heads.

to all
 

guys
thanks to all that have given support, now i'm confused a bit, not unusual for a Canadian.
i like the idea of using smaller cc heads, say 100 cc, i believe that would be a managable cr

i raced this in the 80's, with good results, in street trim, i'm looking for that power out of the hole and if i can achieve will be quite happy.

thanks again to all
paula
great site, good advice from knowledgeable members

The 068 is NOT a big cam.

The gains from going from 8.0:1 to 9.0:1 with this cam will be marginal, no where near as much as we'd see if something like an 041 cam was being used.

I have less compression and a larger cam in my own 455. With a stock torque converter and a 3.08 posi, I can smoke the tires off idle with ease.

Runs fine on 87 octane, doesn't overheat, and is reliable. If it isn't being built to race, then no need to push the limits.