Cam question

glb1948 · July 30th, 2006, 05:11 PM

Here are the vitals. I have a 87 Olds Cutlas with a 72 350 Old Rocket. There is a Comp Cams 268/268,456/456. It has an edelbrock performer rpm intake with an edelbrock 750 carb. All MSD ignition. A TH400 with shfit kit with a 2000-2200 stall convertor and a 9" ford rear with 4:11 gears. I want to use the car for street/strip. My questions is this. On hard acceleration the car will bog slighlty then run super but the valves seem to be floating around 4200 rpms. Does anybody have a suggestion for a good stout cam with a nice lope to it? Any infor is apprectiated...Thanks, Gary

Oldsguy · July 31st, 2006, 07:54 AM

Going to a stouter cam will not fix your problems with bogging and valve float. They may be caused by two seperate issues. Does your bog happen at the start of the hard acceleration? If so, I would look to getting that carb fine tuned, your accelerator pump might be a little too much, or your timing could be off, are you using an MSD ignition box or just the distributor? If you are using the box then it might be able to fix you ignition problem with some adjustments. If the bog comes later in the acceleration it might be related to the valve train and your valve float problem, especially if your heads are all stock. 4200 rpm isn't too much for a small block Olds and you should look into upgrading your heads and valve train. It sounds like you have a pretty good engine/drivetrain build and you just need to massage it some.

glb1948 · July 31st, 2006, 08:31 AM

Dan - Thanks for the reply. Yes, I believe the heads are pretty much stock and I was thinking on going to 455 heads. The bog does come right on acceleration but when it does grab, hang on. It does not seem to bad when I manually shift though. I do have the MSD box with a timing control also but the dist I believe is a HEI with a MSD cap on it. I was also told that maybe a 3,000 to 3,500 stall convertor may help to.

HWYSTR455 · August 23rd, 2006, 09:10 AM

The Edelbrock carbs are known for a transition stumble, and doubt you'll be able to get rid of it without replacing it (pick a Holley Avenger 670 or 770, or a 3311 750 Holley). As for the 'float' you mention, it may be the lifters are chinese junk. Comp had an issue with lifters for some time there, and ended up 're-valving' them with a slower relief internally. Aside from that, I would suggest using the 'Johnston' lifters which are now again available. Several manufacturers carry them now. As for the cam, are those 'advertised' numbers you posted? Seems kind of small, especially with those gears. I would suggest a split-lobe design, and shoot for the mid-220s on the intake, and low-to-mid-230s on the exhaust, like the Comp XE268, or XE274. I like the Crane grinds, like the H-284-2, or the H-272-2, which are the comparable grinds to the COMPs (they have a 112 CL, which gives better idle qualities).

July 30th, 2006, 05:11 PM	#1 (permalink)
glb1948 Junior Member Join Date: Jul 2006 Posts: 2	Cam question Here are the vitals. I have a 87 Olds Cutlas with a 72 350 Old Rocket. There is a Comp Cams 268/268,456/456. It has an edelbrock performer rpm intake with an edelbrock 750 carb. All MSD ignition. A TH400 with shfit kit with a 2000-2200 stall convertor and a 9" ford rear with 4:11 gears. I want to use the car for street/strip. My questions is this. On hard acceleration the car will bog slighlty then run super but the valves seem to be floating around 4200 rpms. Does anybody have a suggestion for a good stout cam with a nice lope to it? Any infor is apprectiated...Thanks, Gary

July 31st, 2006, 07:54 AM	#2 (permalink)
Oldsguy Hot Rodder at heart Administrator Join Date: May 2004 Location: Lees Summit MO Posts: 5,360	Going to a stouter cam will not fix your problems with bogging and valve float. They may be caused by two seperate issues. Does your bog happen at the start of the hard acceleration? If so, I would look to getting that carb fine tuned, your accelerator pump might be a little too much, or your timing could be off, are you using an MSD ignition box or just the distributor? If you are using the box then it might be able to fix you ignition problem with some adjustments. If the bog comes later in the acceleration it might be related to the valve train and your valve float problem, especially if your heads are all stock. 4200 rpm isn't too much for a small block Olds and you should look into upgrading your heads and valve train. It sounds like you have a pretty good engine/drivetrain build and you just need to massage it some. __________________ Dan '77 Cutlass Supreme '46 2 door "The rocket 455.....it's a sledgehammer approach to a thumbtack world" LuxBlue of HAMB.

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Brekes Proportionate Valve	mcutlass1969	Cutlass	3	February 1st, 2007 12:59 PM
door strip protectors?	ztim	Chassis/Body/Frame	1	December 22nd, 2006 02:05 PM
SSII rims HELP	1980oldssherman tank	Other	2	November 17th, 2006 08:28 AM
is a 442clone worth more than a standard cutlass restored to original?	oldsmoenewbie	Cutlass	1	October 28th, 2006 05:46 PM
1985 Cutlass Supreme 307 hesitation	Grinder89	Small Blocks	2	September 15th, 2006 09:16 PM

July 31st, 2006, 08:31 AM	#3 (permalink)
glb1948 Junior Member Join Date: Jul 2006 Posts: 2	Dan - Thanks for the reply. Yes, I believe the heads are pretty much stock and I was thinking on going to 455 heads. The bog does come right on acceleration but when it does grab, hang on. It does not seem to bad when I manually shift though. I do have the MSD box with a timing control also but the dist I believe is a HEI with a MSD cap on it. I was also told that maybe a 3,000 to 3,500 stall convertor may help to.

August 23rd, 2006, 09:10 AM	#4 (permalink)
HWYSTR455 Junior Member Join Date: Jul 2006 Posts: 16	The Edelbrock carbs are known for a transition stumble, and doubt you'll be able to get rid of it without replacing it (pick a Holley Avenger 670 or 770, or a 3311 750 Holley). As for the 'float' you mention, it may be the lifters are chinese junk. Comp had an issue with lifters for some time there, and ended up 're-valving' them with a slower relief internally. Aside from that, I would suggest using the 'Johnston' lifters which are now again available. Several manufacturers carry them now. As for the cam, are those 'advertised' numbers you posted? Seems kind of small, especially with those gears. I would suggest a split-lobe design, and shoot for the mid-220s on the intake, and low-to-mid-230s on the exhaust, like the Comp XE268, or XE274. I like the Crane grinds, like the H-284-2, or the H-272-2, which are the comparable grinds to the COMPs (they have a 112 CL, which gives better idle qualities).