12.89:1 CR...doable? E85 maybe?

[Superdave]

you know there is a difference between a turbo cam and a N/A cam right?


stock rods are good for 7K, much higher than that and they'll be hanging out of the side of the block.

[2.8/3400 1985 Camaro]

Well there is also another factor with the cam which is max RPM and high RPM powerband, its the highest I've found for the engine with 3-7k and 8k+ redline, perfect for a big turbocharger to hit my goals.

[Superdave]

mine or for a suggestion?

220 ish at .050 is around what i was thinking...


mine is 232/238

[IsaacHayes]

Dave what actual duration @ .050?

[Superdave]

HVAC is the other one plus the trans if it's an auto.


You can go with a smaller cam and still get the desired results. At the very least you'll have to run premium fuel but i wouldn't get too stuck on the numbers game. There are other variables involved besides SCR and DCR that determine what types of fuel you can use.

Your cam selection should be based upon the desired operating range of the engine, port flow of the top end and supporting VE improving mods like headers, bigger TB and porting.

For stock 3400 heads something around .5 intake and .5 exhaust lift, 260-270 advertised on a 110-112 LSA is pretty decent. That will keep the overlap down in the 50-60 degree range.

[2.8/3400 1985 Camaro]

3400 top end swap, which is why i want a cam that huge to compensate for compression, not to mention huge power gains, but I also might be getting a 350 tpi trans am, in which case I might just build the camaro for racing...Don't know yet, going to talk to the person more about it today. Aren't brakes the only vacuum driven accessory?

[Superdave]

no, i didn't add the 15.


That's a race only cam. Probably circle track, sandrail or for a '660 powered boat. Under normal driving it's going to need a pretty high stall converter, your brakes and other vacuum driven accessories will barely work and probably non-stop tuning. Since it's a mechanical cam it's also going to be noisy and you'll have to adjust the rockers a few times a year.


I run a pretty extreme cam in my 3500, trust me.. if you enjoy driving the car go with something a little more tame.


I think something like the Lazer cams 2700122 would be a better choice..

3rd up from the bottom: http://members.shaw.ca/betterthanyou...haft_guide.htm

It depends on what heads you are using as well, that much cam on gen1 or gen2 heads is a waste of time.

[2.8/3400 1985 Camaro]

That would put dynamic CR at 11.363:1, I'm assuming you already added the 15 degrees into the 48. Now I don't suppose anyone knows the DCR on stock gen 1 2.8? or the cam's ICP?

[2.8/3400 1985 Camaro]

Well where is the issue with driving that on street exactly? I mean yeah, 1300 rpm would be a really high idle speed, but what effect does that have on driveability exactly?

[Superdave]

IVC (ABDC) would be 48.0 @ .050

[geoffinbc]

Over lap does not tell the whole story. Pressure bleed off depends mostly on the IC event. The later is closes the more pressure will bleed off. You do not necessarily have to have a lot of overlap or duration to bleed off cylinder pressure.

[IsaacHayes]

Well, with a huge ass stall, or 5spd it might be drivable with that idle.. LOL... manual you could just slowly let out the clutch without touching the pedal probably.... hahaa

IVC ABDC spec you need to get from crower..

With that much overlap, it should bleed off a ton of compression I would think.

[2.8/3400 1985 Camaro]

How will it do with that kind of CR though, well enough for to run pump gas?

[Superdave]

you won't be able to drive that on the street.. that cam has 79 degrees of overlap. It will have to idle at 1300 RPM.

[2.8/3400 1985 Camaro]

I'm getting a solid flat tappet from crower with a 3-7k powerband and 8k+ redline. 248* int and 250* exh @ .050 lift, and .501 gross lift on intake, with .511 exhaust.

If someone could explain the below thing or tell me what # it is from those above that would help in that i could find the dynamic CR.
"Intake Closing Point (degrees)ABDC @ 0.050 lift plus 15 degrees"