Flat Vs. Roller

[Johnny Blaze]

WHat differences would I get between a flat tappet solid lift cam and a solid roller cam?

What would the real world differences in powerband, peak numbers, etc,

Here are the two that I am looking at,

Comp soild flat tappet 51-246-4 Grind number 294S

Solid, Rough Idle, need higher compression ratio. MAximum street Preformance. USe 300 stall and low gear.

Valve setting .022 Rpm Range 2500-6500

Duration @ .050 248 / 248 lift .525" / .525"

Lobe seperation angle 110

Comp Soild Roller 51-751-9 Grind Number 288R

Mechanical Roller, Choppy idle, broad power range, increased compression advised with 3000 stall, headers, and lower gears.

Valve setting .020 Rpm range 2200-6500

Duration @ .050 244 / 244 lift .550" / .550"

Lobe seperation angle, 110


Would the rooler cam make enough difference to justify its cost?

This would be going in a Pontiac 400, with 9.5:1 compression, edelbrock heads, PRM intake, headers, etc..

5 speed with 3.73 gears.

[SStrokerAce]

The roller has less overall duration so it will idle better plus it will make more TQ. You can also make more power because of the higher lift. Add in that you are not going to wipe out a cam lobe if the block isin't perfect.

I would probably go smaller on the roller than that and add a little more lift.... only problem is you can't go too crazy in a Poncho block with roller cams without hurting the block.

Bret

[Johnny Blaze]

Thanks, so what kind of hp or tq increase whould you think? Is it going to be worth the $300 more?

[Lowend]

A roller cam is better from several standpoints. Peak HP numbers may not be drastically different, but the powerband will be much wider.
Also, I believe the Pontiac motors suffer from similar cam oiling problems as the BBC (I'm not Mr Pontiac by any means), if this is true a roller cam will have much better longevity than its flat tappet cousins.
I suggest you consider a cam with a a little extra duration on the exhaust side, 5-10 degree's max. I know the Pontiac has a poor flowing center exhaust port, and the extra exhaust duration will help counter act this.

[ProdigyCustoms]

The problem I see with both of these cams is they will make power north of the Poncho safetly zone of 5500 to 5800. The skeleton lifter valleys are VERY weak, and hate lots of lift (although a roller will help this stress), but the motor masically hates RPMs, so make it a torque monster.

For Pontiacs, I have become very confident with Jm Butler performance

[Johnny Blaze]

The roller listed here, is actually smaller than any listed on Butlers site!