Custom Made Grind Cam ; tell me what you think

[SwaveDave]

It will be a CompCams Hydr. Roller . , used for street only .

240/245 duration @ .050 "
lift is .613/.613
Lobe Seperation is 114
110 centerline
Valve Timing : Intake open 10
Intake close 50
Exhaust open 60
Exhaust close 4

SwaveDave

 

[Tom Bryant]

Dave,

From the specs in your signature it looks like a good match. Was this their recommendation based on your engine? If it was I would say go for it.

Tom

 

[SwaveDave]

Tom,

They made the duration and lift recommendation, and i made the LSA of 114 recommendation. Im not too worried about it going 'rumpity rump' at idle although, i dont want a huge lope. I was hoping the 114 LSA would help in that area. I did want to build some power though with the duration and lift, and since its not driven in city traffic hardly at all, i thought it would be good for my weeknight and weekend drives out in the country and on 2 long trips i make each Fall to Corvette Festivals.

Any comments on how you think the driving characteristics will be on this cam Tom ?? My engine description will be soon changed to : 468 cid / 560 h.p / 625 tq / new Manley H Rods / new TRW 9.6 CR Pistons / new Hydr. Roller Lifters / and this custom grind Hydr. Roller Cam. Entire rotating assembly will be balanced.

Thanks.

Dave

 

[Tom Bryant]

Did Comp Cams give any idea of what the cruise rpm with this cam would be? As long as your rear gear will put the engine in that range at your favorite highway speed it should work out well. It doesn't look like mpg is a big issue with this car. :L

Tom

 

[SwaveDave]

Tom,

3000 rpm cruise. For me, that is 70 mph. Id say i do between 60-75 mph on my long trips on the highway.

Cam range is 2500 to 6000 rpms.

Desktop Dyno says my h.p max's out at 5500 rpms, and my torque at 4200 rpms. Shes mostly low end to midrange torque - exactly what i wanted for a street machine. I was getting 13 mpg combined driving with my old setup ; i expect to get 11 when i get her back . But...shes only a 2000 mile per year car , so Amoco Oil Co. doesnt make too much off of me

Had trouble finding Pistons that were full floating pins at 10.5 CR...so had to settle for 9.6 CR. Speed Pros. Youd think there would be a better selection wouldnt you ? Oh well, maybe with the lower friction of full floaters, ill pick up a few h.p. to make up the diff.

Dave

 

[Stingray72]

I have a theory that idle characteristics are determined more by advertised duration rather than duration at .050". If the advertised duration on that cam is kept in the 280-295 range, I would hazard to guess that you'll have a relatively smooth idle, but your lift numbers might disprove that guess. That's great lift for that duration (characteristic of rollers). Should be a fun cam.

 

[69MyWay]

Had trouble finding Pistons that were full floating pins at 10.5 CR...so had to settle for 9.6 CR. Speed Pros. Youd think there would be a better selection wouldnt you ? Oh well, maybe with the lower friction of full floaters, ill pick up a few h.p. to make up the diff.

Dave

Dave, I guess you will be running the same exact ones I have in the 69. All I can say, is order them now. Back when I did it TRW/Speed Pro, etc. was going through some huge changes. I ordered the pistons in like August 01, and got them in December!

They are the full floating models as suggested by Edelbrock in the RPM package.

Up until now, our long blocks have been pretty close in specs. Any reason why/what prompted you to make these changes you are considering now?

 

[SwaveDave]

72,

I just hope i didnt overdo it by going with a big duration . We shall see. Ill report back , after i get it back.

69,

The pistons im going with are L2399F060 TRW full floating pins, 9.6 CR . The reason i went with these instead of a higher CR is because i could not get any 'in stock' at Jegs or Summit that were full floating. My mechanic said i want full floating instead of pressed pin because the friction is less . (My theory is, because i went with very small domed pistons , i can now go with a higher cam lift without the piston hitting the valves. Plus of course, i wont have to worry if i can only find 89 octane gas while im out of town on a long trip.)

Dave