[sharkboat]

Hi
I was wondering on input for cam selection for the 455 I am building.
It will be mostly street car with power brakes.
Engine specs 455
bored .030 over 462
factory crank and rods
speed pro pistons
#15 heads (87cc) bigger valves screw in studs ferrea valves (no rockers yet)
edelbrock performer intake
headers
Q-jet carb
trans 700r4 with 2800 rpm stall

1966 lemans convertible 3.90 rear

Thanks for the input

[runningbwdog]

Hi,
I have a similar engine: 462, #15 heads, factory crank and rods, 9:34:1 compression.
I am running a Comp Cam XE-268 with 1.5:1 rockers. Stock manifold and Q-Jet. Mine has M20 4 speed and 3.55 rear gears. Has plenty of low end torque. Runs strong to 5200 rpm. Idle is smooth and has plenty of vacuum for power brakes. I am planning on putting 1.65:1 rockers and headers on it later this year. Also have a Performer manifold that I have port matched and set up for the Q-Jet cookstove choke. Its just to hot to do all this stuff in North Alabama in the summer.
Mike

[Schurkey]

Originally Posted by runningbwdog

Hi,
I have a similar engine: 462, #15 heads, factory crank and rods, 9:34:1 compression.
I am running a Comp Cam XE-268 with 1.5:1 rockers. Stock manifold and Q-Jet.

My build is also similar. I'll have about 9.2 compression; and I was considering the XE-268 cam although I'm leaning more toward the -262 or similar.

DO YOU NEED PREMIUM GASOLINE? I'd like to be able to run low-grade (87--89 octane) if possible--but I don't know what's possible yet.

Originally Posted by runningbwdog

I am planning on putting 1.65:1 rockers and headers on it later this year.

Got the headers already; but I'm REALLY CURIOUS about the gains from the 1.65 rockers (if any). Is that a common and accepted power-gain in the Pontiac world?

[BruceWilkie]

A low dollar pick would be the Summit 2802 hydraulic grind. A good all around cam in a 455+ motor and its not too sensitive to a weak batch of gas. An XE 268 offers too short a seat time IMO(.050 specs should never even be compared here until all other valve event considerations are compared). If you were to run an xe 268 I would not install it at 106 ICL as they are ground to but set it back to 108 to possibly 110 ICL Especially with your trans and rear gear, you end up with more bottom end than you can possibly utilize(unless your pulling semi trailers) and not enough power at the upper end. A Hydraulic roller of similar spec to the summit grind but perhaps a tid larger might be the better way to go(less risk of cam failure on install). Get in touch with PontiacDude (Kens Speed and machine). He has several proven hyd roller combos and can set you up with whats best for you. I'm not going to give away his custom cam specs he uses but they are far better than any shelf cam out there.

[screamingchief]

I would suggest something like the Crower #60243 myself,be it a FTH or HR cam.

Should be perfect for that sorta combo.

But I'd lose the performer intake myself,I'd opt for an OE cast iron intake,or just about any other decent intake out there,IMO the performer just is'nt up to the task of feeding a big cube engine.

[Cliff R]

"Hi
I was wondering on input for cam selection for the 455 I am building.
It will be mostly street car with power brakes.
Engine specs 455
bored .030 over 462
factory crank and rods
speed pro pistons
#15 heads (87cc) bigger valves screw in studs ferrea valves (no rockers yet)
edelbrock performer intake
headers
Q-jet carb
trans 700r4 with 2800 rpm stall

1966 lemans convertible 3.90 rear

Thanks for the input"


Crower 60919 cam, set it at 109ICL. The XE268 is not nearly enough cam for the application, it will be DONE by 4500 rpm's. The Crower grind sports 304/314 degrees duration, with over 80 degrees of overlap, it will pull hard to apprx 5600rpm's in your appplication.

Ditch the Performer intake, it is a restrictor plate on the 450hp 455 engine. Get an early iron intake, HO intake or Performer RPM instead......Cliff

[runningbwdog]

Hi,
Just to be on the safe side, I use 93 octane Shell or BP gas. I don't drive it daily.
I have heard that Pontiac heads can benefit from increasing the flow on the exhaust side. I may start by leaving the 1.5:1 rockers on the intake side and put 1.65:1 on the exhaust side. I'm not looking for a monster engine. I have to be really careful about how much throttle I give it on pull away. Just a tiny bit too much throttle and the rear tires break loose. I hate the evil looks I get when that happens because I interrupt others' cell phone conversations.
Mike

[PITTSBURGH 64]

I like the Crower hyd 60919. I have a 455 (462) with ported 6X8 heads yielding around 9.3 compression.

Globs of low end torque with a smooth powerful power band through 5000+ rpm. Nice mellow controlled lope in idle with 11" of vacuum in gear. No need for Rhoads lifters.

My car has a 2.56 posi.....

http://www.youtube.com/watch?v=2Q6OQ-j13wQ

http://www.youtube.com/watch?v=7qznNTyehIE

Pulling a steep hill with the initial timing mistakingly at 4 degrees. It's usually at 14.....
http://www.youtube.com/watch?v=OmzCa3VZtbk

[sharkboat]

Thanks for the info on the cam.

So I have the orginal intake off the 1970 455 I rebuilt. This is a better option than the edlebrock performer??

Also on the rockers should I go with 1.65:1 or stay with 1.50:1 ?

Thanks

[ta man]

Are your pushrod holes opened up to run 1.65 rockers and can your valve springs handle the additional lift?A perfect spring for you is a 68404 crower.If you are using stock length valves and stock installed height.

[pippintook]

sharkboat - I ran an Edelbrock Performer on one of my 455 combos. I ran 13.07@106.73 (at track) in an 81 TA with 3.08s and stock THM350 (with stock stall) on street tires through the exhaust. My 455 had cast rods/arp bolts, TRW forged pistons, stock crank, #96 lightly ported heads, HC-02 cam, performer intake, qjet and 1 5/8 headers.

Cliff / Screamingchief - Jim Hand states in his book ( 'How to Build Max Performance Pontiac V8s' ) there was no performance difference between the stock cast iron qjet intake and the Performer on his 455 combo. I think Jim's basic 455 combo is/was Ram Air IV cam, Lightly ported D port heads, 68-72 Cast Iron intake, Qjet...not sure of the exact specifics on header pipe size, rear gearing as I believe Jim changed this...Jim's 455 combo would appear to be in the 450hp range...

Any idea why Jim did not see any Performance difference between the Performer and a Cast Iron Intake on his 455 combo ? Do you guys have any back to back testing results that shows the Performer can hurt performance on a 455/450hp when compared to a 68-72 cast iron intake ? I thought the Performer had slighly smaller ports when compared to the 68-72 cast iron intake..but, perhaps the smaller Performer ports helped with port velocity...or a performer could have a tad more area under the HP/Torque curve (even if it might lose a bit of peak HP versus a cast iron intake). On a 455, at what HP levels do you think it makes sense to change from a Performer to a cast iron intake ? Any other advice/comments on comparing a Performer versus stock cast iron intake is appreciated.

[Cliff R]

Unfortunately, I wasn't able to get back to back test results from the Performer vs iron intakes. We purchased one and attempted to run it at the track back to back against the iron intake. When bolted on my last engine, it simply would not perform well enough to make effective dragstrip runs.

The engine surged, hesitated and had some pronounced detonation when attempting to go to full throttle when the Performer intake was installed. When the iron intake was put back in place, the engine performance was fine at all levels.

I tried a follow up test with the Performer intake on a 455 engine on the dyno, with #46 heads (2.11/1.77 valves-mild porting), Crower RAIV cam, etc. Basically the same engine that powered my car that made 455.4hp. The best pulls we could come up with after tuning it all over the place were 440hp. I've never attempted to run one since, and don't use or recomend them for a 455 engine.....Cliff

[SRR]

I would up grade to a good set of rods. Why take chances.

[uforacing]

I would have to go through some pictures I took that day but I think there was a spacer bolted to the Performer on the wagon for the test. I do remember that the high hopes he had for the RPM were not to be on that combo that day. This was the summer of 92 at KCIR when the tests took place.