[ponyakr]

"...Everyone says you cant run a decent sized cam with low compression..."

I think the SD455 should prove that a low comp engine can make decent power with a decent sized cam. They were rated at 310hp, with an 041 spec cam. And that was a net rating, for '73 models. I assume the actual flywheel hp was likely well north of 350, and with some ignition and other tuning upgrades, would have easily approached the 400hp mark, if not a bit over. And, even the 744 spec cam, which ended up being the SD455 production cam, is thought by many to be good only for high comp engines.

If they had used the 041 cam, instead of the little 068, the 455HO engines would have also made good power, with low compression.

[PunchT37]

Originally Posted by 72LuxuryLeMansLa.

I may regret this but here goes. Engine analyzer Plus graphs. I used the 70's era low compression 455 file by Rocky Rotella with the 067 cam as the engine to test. Probably what the op has. One shows the 067 vs 068 and the other has the Voodoo 701 vs 702. All runs were sae settings with 87 octane. After doing this test I would not go from the 067 to the 068 cam because it will just shift the torque curve up. I would look to a Voodoo or similar grind or leave it alone. In my mind there just is not much to be gained with an 8:1scr 455. If you can't raise the compression it is just a truck engine. Now I have no real world experience building Pontiacs so take it for what it's worth. I don't try to pass myself off as an expert. At this anyway.........

Wonder how the Crower 60241 would run in this app.?

[Lee]

Originally Posted by Bruce Meyer

I went 12.70 in a 3965 pound car with a 455 and 8:1 compression. I used a Ultradyne cam that had 239/247 duration on a 112 LSA. The key was Rhoads lifters. If you can stand the ticking sound you can make HP with good street manners. With a bone stock 8:1 455 I would use a Summit 2802 with standard lifters or a RA4 copy with Rhoads lifters. Everyone says you cant run a decent sized cam with low compression. They are wrong. Most of the people that say this never had any experience with hot rodding a low compression combo.

Heads/cfm? Stall speed & gears?

[72LuxuryLeMansLa.]

Originally Posted by PunchT37

Wonder how the Crower 60241 would run in this app.?

When I get back to my desktop I'll run it.

Sent from my SAMSUNG-SM-G900A using Tapatalk

[Bruce Meyer]

Originally Posted by Lee

Heads/cfm? Stall speed & gears?

stock 71 HO heads. I had them tested and they flowed only 10-15 more cfm than 6X heads. 3.73 gears. 11 inch 3000 stall. Ended up putting ported 6X heads on it and it ran 12.17.

[72LuxuryLeMansLa.]

Originally Posted by PunchT37

Wonder how the Crower 60241 would run in this app.?

Do you have the specs on it? Their current catalog has the 60243 but no 60241.....

[PunchT37]

https://www.crower.com/searchresults...=60241&x=6&y=6

[72LuxuryLeMansLa.]

Originally Posted by PunchT37

Wonder how the Crower 60241 would run in this app.?

Voodoo 701 vs Crower60241

[PunchT37]

Cool. Wanted to see how a fast ramp did against an "old school" cam.

[72LuxuryLeMansLa.]

Originally Posted by PunchT37

Cool. Wanted to see how a fast ramp did against an "old school" cam.

Yup. These programs are great for looking at those broad trends without having to change cams in an engine. But of course as you have pointed out in the past to KNOW for sure you are required to get your hands dirty......

[Interceptor]

Originally Posted by Lee

I just installed a 222/242 @ .050" on a 116 LSA in my 7.8:1 455 with stock heads. Custom low-lift from Bullet, my specs. Log manifolds for now, but plan on headers in the near future, I'll dyno test before and after. Quite happy with the cam so far.

How did this turn out after tuning and driving? I was thinking of a Voodoo 703 for my 70 TA 455 3.23 rear gear clone -- I have the 702 in my GTO 400 and it runs great at 9.3:1 but I thought it would be tame for a 7.8:1 455. Your specs are interesting.

What is the stock cam in a 1975 455?

[moontower69]

Originally Posted by PunchT37

Wonder how the Crower 60241 would run in this app.?

I run the 60241 in my low compression 389 and, for what it's worth, it's pretty STOUT!
Smooth idle but pretty much an animal on the street when you get into it (no track times). 20ft burn outs off the line at will and can get side ways shifting into 2d.

Comes on strong from about 2600 to 4600. It shifts to 2d at about 5500 but feels like power noses over at 4800. Pretty good bottom end but a tad lazy off idle (my only complaint). I imagine for a street 455 it would be equally stout.

Combo is a 389 (60 over) with 92cc #11 heads (2.11/1.77 valve upgrade) and 1.5 rockers. Zero decked, compression is 8.6:1. Holley 650 SA, ram air manifolds, 2.5 mandrel duals, x pipe w/ Dynomax STs (a little too quiet actually) and 5140 rods and 4.12 TRW slugs and stock crank. Built 700R4 with 3.55 posi and 2000 stall and 28" 235/70/15 tires.

670 Holley SA was a pain in the ass to dial in. Had to up squirter to 35 and up the jetting up 70 and 76 (from stock jetting of 65 and 68), orange cam.

Curious if a Voodoo would run any better give the low compression (maybe the 702 with 219/227 duration) or Summit 2801. My guess is very similar performance?

[Cliff R]

"Everyone says you cant run a decent sized cam with low compression. They are wrong. Most of the people that say this never had any experience with hot rodding a low compression combo."

+2, 3, 4 and 5!

I would NEVER under any circumstances put a cam with less than 230 @ .050" in a 455, even one with relatively "low" compression.

When over camming or not quite "optimum" compression either go to a roller profile with less actual seat timing, or flat tappet with high ratio rockers and Rhoads lifters. The flat tappet/high ratio rockers/Rhoads lifter combo will mimic the power of the roller at much less cost.

The big 455 will not see a 230 @ .050" as a huge cam. We've done a number of HO and Pontiac Super Duty 455's which were all under 9 to 1 compression and made great power with them, all 1hp/CID or greater, and retained good idle, off idle and strong power in the "normal" driving range.

Below is a dyno sheet from a 455 with only 9.3 to 1 compression, and made great power once the builder installed the second cam we recommended for it........Cliff

[skullbucket]

I have never ran a Voodoo cam, always wanted to try one but I really like the "Comp Cams magnum" series, they have great power and sound mean.
Years ago it was the "Crane Cams brand" But their specs and descriptions seemed to change and I couldn't find anything that would work.

[moontower69]

Anybody tried the 60242 (221/229) in a low comp 455? Based on Cliffs experience curious if that would run well in the “normal” driving range or still leave a lot on table and/or risk detonation? I see a 455 in my future!

[Cliff R]

Here is a cam card for the smallest cam I've ever tried in a 455 engine build, at least since 2000.

I did put an HO racing 744 variant in one decades ago before I had educated myself in how to make power with one of these engines, at least "optimum" power on pump gas.

The engine that cam went into was a .030" over 455 Super Duty, zero decked with Icon pistons, Eagle rods, and .039" head gasket. Heads were cut slightly to clean them up, so compression should have came in around 8.5 to 8.8 to 1.

It idled dead smooth, no lope, and 13.5" vacuum and still smooth idle clear down to 600rpm's. Initial timing was set at 12 degrees.......Cliff

[Will]

I asked this same question awhile back because I have the exact same engine. '73 455 out of a Grandville with 85k miles on it. Engine runs perfect with just the lightest lifter tick.

I've pretty much decided to go with the summit 2802. The goal is to wake this engine up at lowest possible cost and that should get the job done.

As everyone else is saying, the 455 is a big engine and the lack of compression isn't as big of a handicap with all those cubes as with a smaller engine.

[Steve C.]

Stage 1 (The Daily Driver) 276/288 (224/230 @ .050) 108 LSA .567"/.521" LIFT

Good cam for building HP in smaller applications.

http://www.sandovalperformance.com/camshafts


.

[Lee]

Originally Posted by Interceptor

How did this turn out after tuning and driving? I was thinking of a Voodoo 703 for my 70 TA 455 3.23 rear gear clone -- I have the 702 in my GTO 400 and it runs great at 9.3:1 but I thought it would be tame for a 7.8:1 455. Your specs are interesting.

What is the stock cam in a 1975 455?

Project is ongoing, but I'm quite pleased so far. 225rwhp with stock log manifolds and <2" headpipes. I then installed tri-Y headers, but retained the rest of the exhaust (2" tailpipes, not a great system) and jumped to 270rwhp, and picked up 55tq @ 4500. VERY responsive with a stock torque converter.

The car is currently getting the exhaust upgraded. My exhaust guy is actually retired, but does some work at his house between fishing, duck hunting, and grandkid time - so I have to be patient with him :-)

[pastry_chef]

Originally Posted by Steve C.

Stage 1 (The Daily Driver) 276/288 (224/230 @ .050) 108 LSA .567"/.521" LIFT

Good cam for building HP in smaller applications.

http://www.sandovalperformance.com/camshafts

.

Thanks for sharing Steve, their site is excellent!
A fair bit there on cams, strong valve timing understanding.
The name is VERY familiar, I wonder if they were in EMC

Another member Gary ran the 'small' Voodoo 702 - http://forums.maxperformanceinc.com/...7&postcount=34