Special 300 HP engine configuration technical documents

[Duke W.]

Due to recent discussion of the Special 300 HP configuration with the McCagh Special camshaft I've attached the "Tale of Two Camshafts" article that was published in The Corvette Restorer about ten years ago, the Special 300 HP technical support paper, and the compression ratio management paper.

Though the tech support paper applies specifically to the Special 300 HP configuration, most of the general recommendations apply to any precision rebuild.

Duke

[Bob W.]

Re: Special 300 HP engine configuration technical documents

Duke, Thank you for posting this information as it will be helpful to anyone looking to rebuild their motor

Thanks Again Bob



Also can this be done to a 350 block?

[Duke W.]

Re: Special 300 HP engine configuration technical documents

Sure it can, 383s too. The only real difference between a 327/300 and a 350/300 is the stroke, nothwithstanding the different carbs, which are not a major factor.

On 383s with manual transmissions I recommend retarding the McCaw special as ground four degrees to a IPOML of 120 ATC, but install it as is with automatics.

Given the relatively low cost of new high quality 383 cranks and pistons (and the same aftermarket rods as any other small block), it makes a lot of sense to put a 383 crank into a 350/300 and with the massaged heads you will have about the same torque/power as a 427/390 that looks like a plain old base 350.

Duke

Duke

[Mark P.]

Re: Special 300 HP engine configuration technical documents

Thanks for posting this Duke.

[Gene M.]

Re: Special 300 HP engine configuration technical documents

I‘d like to get a reading from Mike on the “McCagh Special camshaft“ if it is any good. There are a lot of commercial available grinds that produce good mid range power with stock character. I not talking race stuff,but for performance street driving.

[Duke W.]

Re: Special 300 HP engine configuration technical documents

So send Mike an email and ask him, unless he responds in this thread.

Did you actually read the "Tale of Two Camshafts" article? It's all there, including the lab dyno test that yielded more GHP than the advertised rating of the '61 283 FI engine with the big port heads and Duntov cam, which was probably overrated as most small blocks were in that era. Plus it idles butter smooth and stable at 450 in Drive, just like a 283/250 FI engine should.

The trouble with aftermarket "performance" camshafts is that they all have more effective overlap than the McCagh Special, which would likely fail a PV due to idle behavior, so maintaining base cam engine idle behavior was a basic requirement, and Mike passed the PV and went on to win the Duntov Award.

Duke