400 Cam Selection
 

I had my 6th procedure (a scope this time and I'm told the last needed.....) 6-8 weeks ago on my right shoulder, in celebration, I decided I'd do a ball hone rebuild on my 400 and put it back in the GTO. The 400 currently has a 220/224 Comp hyd roller cam in it, but after pulling the heads I believe that cam was on it's way out due to a very small bad spot on that one lifter roller. When I put the 400 together I went with the 220/224 (110 lsa) because the GTO was an auto. All these years later its now a manual and I'd like to put a little more cam in it. I was thinking 230/236. The 455 I'll be taking out has a 230/236 (110 lsa) Comp in it, currently set up as a "hybrid" with Crower hippo solid roller lifters. Besides the manual trans (TKO600) the car now has a 3.73 rear.



I could simply swap the 455's 230/236 and solid roller lifters into the 400.

I could use the 455's cam and use the set of Comp hyd roller lifters I have in the cabinet.

I could buy a new cam and use the hyd roller lifters I have in the cabinet.


Vacuum isn't really a problem, I have hydroboost brakes and the hideaway doors don't seem to care. I'm not looking for a lot of rpm, the bottom end (rods/crank) is mostly factory. I will replace the bearings/oil pump while I'm in there. The pistons are thirty over TRW's, so compression is 9.5ish to one. The heads are 48's that Pontiac Dude refurbed/cleaned up/lightly ported for me about 10-15 years ago. They are on the workbench now and I'm cleaning the little bit of crud off of the intake valves and generally getting them ready before I look further into the shortblock.



This will be a months long process and I hope my metal/plastic shoulder and my jack stands on the basement floor work environment won't hinder me too much. :)


Thoughts?

Do I read you right here, your taking out a 455 with flat top TRWs that had casting number 48 heads on it and you say your compression was only 9.5?

If I am wrong and your saying the 400 will have a 9.5 comp with the 48 heads then I have to assume they are the 72 CC version.

If that’s the case and you want to run that cam from the 455 I would then like to
See your compression increase to 10.25 to 1.

I wish you the very best with this rebuild and hope it all goes well. I too have "artificial parts" in my body and understand yur concerns. You'll get good advice here and may all go well with you and your GTO!

I think you will find the 230/236 on a 110 LSA will work better in your 400 than it did in the 455. Especially with the solid lifters on it.

Compression is a bit "low" for a lot of camshaft, so I'd go with a smaller HR profile. The cam listed below would be fine for what you are doing although I haven't done a 400 build myself using it but several of my customers have and good feedback from them.......
https://forums.maxperformanceinc.com...1&d=1681307455

This is from the cam that's in the 455 that I'd put into the 400. I didn't realize I had a picture of the cam card in the archives. Ken Keefer called it the "Butcher Special". Cliff, the lobes are the same, mine is on a 110lsa. The rest of it is Greek to me.
https://forums.maxperformanceinc.com...8&d=1599939766

Here comes the dyno sheets.

Many thanks. After it's all said and done, I've had a reverse replacement of my right shoulder. Actually, I've had three of those, among other surgeries chasing a bacterial infection in the shoulder. I'm still in the "what is possible....and safe" learning mode. Doc has given me guidelines and since I really haven't been "well" in about 5-6 years, I'm not completely sure what my new "normal" is. These are my new parts.....



https://forums.maxperformanceinc.com...1&d=1681311698

What's a cam thread without a few dyno sheets? :)

I'm running Comp's Extreme Energy version of this cam 51-423-11 in a stroked 350 with the Eagle 4.25" crank (413 cu in) and the 6X-4 heads and am very happy with the performance. Idle was manageable even at 600 RPM and peak power was coming in at 5600 RPM. Compression ratio calculated out at 9.13

This is the exact cam I have in my 433 with 9.8CR. Very happy with it, very responsive, ground on 112lsa exactly like the cam card that Cliff posted. Before I bought the cam discussed with Dave at SD about the lsa and he recommended 112 lsa.

That cam in the 455 SD build I did here made 16" vacuum at idle speed and dead smooth, not a hint of lope anyplace. Below is the dyno sheet from that engine. I'd also add that I had Crane Gold Race 1.65 rocker arms on it and still DONE just past 5000rpms. So basically it's a little "small" for a 455 build with good flowing heads but makes good power (torque). In a 400 build it would work better even pulled down to a 110LSA......IMHO.......
https://forums.maxperformanceinc.com...1&d=1681381905https://forums.maxperformanceinc.com...1&d=1681381933

Isn't that Air Fuel Ratio kind of lean?

Stan

I didn't have A/F ratio on my charts, but his bsfc numbers are in the exact neighborhood the tech guys at Reher-Morrison Racing targeted for best power when we dynoed mine. The air valve on my Q-Jet was not opening smoothly and the engine was running anywhere from .545 to .565 during the initial pulls. We were getting almost 400 lb ft of torque at 4000 RPM but only 330-340 HP around 5200 RPM.

With some tweaking on the carb, we got the bsfc down to .513 and the torque went to 442 lb ft at 4400 RPM and 388 HP at 5200 RPM. Then they determined they weren't getting a clean signal off the MSD distributer causing almost a 500 RPM delay in readings. Their manual calculations with the same torque number yielded 453 HP at 5600 RPM. You can see the extreme lag in the numbers in the video:

https://www.youtube.com/watch?v=cfso2r9udv8

We were running the engine out to an indicated 6000 RPM and it always seemed to be pulling harder at the very end of the run, so we did the last pull out to an indicated 6250 and that's really when the bsfc numbers started coming down.

Not sure what the RPM limit is on the Johnson Hyd rollers Butler supplied for the build, but I didn't want to push it any further without accurate tach readings. I'm thinking it should be good to 6500 though.

350 Block bored 60 over with Eagle cast 4.25" crank
Eagle forged H beam rods and Ross forged pistons
6X-4 heads, all valve spring seats machined to correct height
Torker-I intake, port matched
800 CFM Quadrajet from 1971 Buick GS455 Stage-I, modified to Stage-II
Comp 1.5 roller rockers, Comp springs
Comp XR276HR cam (this one has 110 degree LSA)
Johnson Hydraulic Roller Lifters

"Isn't that Air Fuel Ratio kind of lean?"

Nothing was hooked up to measure A/F so I don't even look at those numbers.. I may gander at BSFC but the dyno operator is used to those numbers not being as "clean" as some of the Holley style carbs they use, but those "ugly" Q-jets still make as much as and often more power on back to back pulls.......FWIW.......

BSFC numbers tell you how efficiently you engine is using the fuel. But don't tell you anything about what the Air Fuel Ratio is.

Stan

Correct, but these days I could really care less about A/F on the dyno. I tune timing and fuel curves for best numbers and don't even look at any of that stuff. I other words ALL of my engines have custom built/tuned distributors and carburetors on them with proven set-ups in them. This saves countless ours of wasted time on dyno day. Early on I used to look at it, but using tunes I've already dyno/track tested for carbs/distributors we're not even close to running lean or putting too much total timing on them. So seeing high EGT's or beating one of my engines to death on the dyno just isn't going to happen. What I've found with those things, especially A/F is that you really aren't chasing much power, assuming you know what you are doing and pretty close right off the bench.

When I get the same engines to the track we messed around with on the dyno chasing A/F, the difference from running "pig" rich to so lean I noticed some "surging" in high gear was only hundreds of a second differend in ET. For that reason I simpy er just a tad "fat" with the carb tune and don't worry about or chase that deal around much.......FWIW......

The actual CC of your heads….calculated compression ratio is an important factor.
I’ve personally found 48’s can vary a good bit in chamber volume.
Good luck with your Bionic parts!! 😎

Thanks. Gonna give it a shot.


The 48 heads came on the car when I bought it 23 years ago. The car also had a 69 8.2" 3.55 "N" posi under it. 2nd hand I was told they both came out of a wrecked Judge and ended up on my car. My car was built with a peg-leg 3.23. No matter the discussions about what 48 heads CC at, I think if my 48 heads originally came on a 400, they'll be 72cc or thereabouts. IIRC, Ken (Pontiac Dude) put hardened seats in them when I had him do the heads? Based on 72 and factoring in valve reliefs, gasket, .04 in the hole, .030 over etc, I'm in the 9.5-1 area. It had no issues with 93 octane before I pulled it for the 455.