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

[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]

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.

[IsaacHayes]

Dave what actual duration @ .050?

[Superdave]

mine or for a suggestion?

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


mine is 232/238

[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]

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]

I know about the rods, and can't a high perf N/A cam typically be used for turbocharging as well? Or would there not be enough exhaust on it? I basically want a cam that will work well enough N/A but also do well with turbocharging when I get there, and in the meanwhile I would only redline at probably 6.5k, but I can't even go that high without new valve springs.

[Superdave]

Turbo cams are designed to have less valve overlap, have a look at the boost cams on wot-tech and go to Comp's website and look at boost cams for the SBC. Notice the higher LSA's


The cam you were talking about earlier would be terrible for boost.



My suggestion is to do one or the other, build a N/A motor or build a boost motor. You aren't going to be able to do both.

[2.8/3400 1985 Camaro]

So where can I find a good turbo cam of at very least 6k rpm, my power goals are 500-700 hp for turbocharging, which If I go that route means dished forged pistons, 3.1 crank ported 3400 heads and manifolds.

[torq455]

if everything goes perfect with the build, i bet you'll be lucky to get 500 hp out of that set up.

[2.8/3400 1985 Camaro]

I disagree...there's guys putting out over 400 on iron heads and manifolds with boost, I see no reason a hybrid can't reach 600, I just read that one of them is after 600.

[robertisaar]

I just read that one of them is after 600.

we all shoot for the stars, but sometimes, it just isn't possible... who is it BTW?

[2.8/3400 1985 Camaro]

Old 02-21-2010, 10:08 PM #33
project89
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Join Date: Apr 2008
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Car: 89 RS
Engine: 3.1 w/ 60-1 Turbo
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Re: I want to see some #s for big power 2.8/3.1s
yeah without those issues it would have made around 400hp/500-525 ftlbs

svcary part was we were prepared to dyno the car at 28 psi that day we did dyno was going to try to hit the 600hp mark
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[Superdave]

So where can I find a good turbo cam of at very least 6k rpm, my power goals are 500-700 hp for turbocharging, which If I go that route means dished forged pistons, 3.1 crank ported 3400 heads and manifolds.

Upgrade to a Gen3 block, then you can get modern parts and might actually meet your power goals.

[2.8/3400 1985 Camaro]

Not even remotely worth the trouble, I don't have the resources to do it myself and no shop would want to, besides which If I have to retrofit an engine it's going to be a v8.