Guidance on cams : 3.2 build - Twin Plug, 10.5, PMOs

[superninety]

Building a 3.2 with twin plug, PMOs and 10.5 CR. Going into my 1970T.

Ive seen guidance on other 3.2 builds but have not yet found such on this particular build.

Running SSI and a Sport Dansk muffler. Have those on hand.

Much appreciated !

[pocv0]

I would contact Dema Elgin or one of the other reputable camshaft grinders like DRC, Web, and give them your specs. They will recommend the proper grind for your application based on your build and intended use ( Track, street rod, occasional auto X ) . I have a similar build with Webers and I went with the Mod S grind from Elgin.

Howard

[superninety]

Yes. Will call Dema for one. He did my 964 cams.

[Classic 911]

The 120/104 cam from WEBCAM is a super profile for a 3.2 build. Real strong and willing all over the powerband.

My 3.2 short stroke has that profile and puts out 290ps and 336,5Nm 254 ft/lbf


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[Jonny042]

I'd email John at Dougherty Racing Cams. He contributes his knowledge to this forum often.

Guessing he'll steer you towards DC43-102 or DC44-102. You'll probably need to upgrade valve springs.

Good luck!

[pkabush]

Don’t count out William Knight. I’d definitely be in contact if I had a similar build.

[Henry Schmidt]

Originally Posted by superninety

Building a 3.2 with twin plug, PMOs and 10.5 CR. Going into my 1970T.

Ive seen guidance on other 3.2 builds but have not yet found such on this particular build.

Running SSI and a Sport Dansk muffler. Have those on hand.

Much appreciated !

Two questions:
What is the intended use/purpose of your end product?
What is the minimum octane of the fuel you will use?

At 10.5:1 your dynamic compression becomes critical. Even with twin plug, these engines have the propensity to detonate. If your plan is to run street gas, 10.5:1 is too high for most street friendly cams.
Given the fact that you are using SSIs, your high rpm potential is limited. With the 3.2 short engine, we generally expect the potential horse power to be around 260 @6800. Given those numbers, we like the DC60. It's fun to drive, offers low enough dynamic compression to mitigate detonation (not eliminate the potential) and leaves a little on reserve if you choose to transition to a more appropriate exhaust system.

[superninety]

Henry, thanks for the note.

Street motor. Hill country driving in Texas. 93 octane.

I was not originally thinking Short Stroke but have access to another crank. I wasn't really thinking high rpms. More low end.

What exhaust would you recommend instead of the SSIs, Henry ?