Comp, S/C, Street 427 BB Engines

[ACademic]

I think the OP might be interested with the internal differences, i.e. compression ratios, camshaft profiles, etc. I'm pretty certain the full competition engines were running at least 12:1 compression and perhaps as high as 14:1. Would be interesting to see a comparison of the actual compression and cam specs for comp vs. S/C (to see how much Carroll had to detune the cars to sell them as "street" runners).

[Cobra #3170]

Originally Posted by ACademic

I think the OP might be interested with the internal differences, i.e. compression ratios, camshaft profiles, etc. I'm pretty certain the full competition engines were running at least 12:1 compression and perhaps as high as 14:1. Would be interesting to see a comparison of the actual compression and cam specs for comp vs. S/C (to see how much Carroll had to detune the cars to sell them as "street" runners).

They did not detune anything, they used stock dual 4 medium risers in the majority of SC's.

The race cars had single four NASCAR engines.

[Bernica]

Originally Posted by Cobra #3170

They did not detune anything, they used stock dual 4 medium risers in the majority of SC's.

The race cars had single four NASCAR engines.

And the race cars had the big NASCAR 4bbl with unique (and rare) NASCAR float bowls.

[DanEC]

Colin Comer's book, "Shelby" has a breakdown of engines used in the 427 models listed by serial number groups on page 86 and some of the particulars of the engines on page 65. Probably the best concise breakdown and listing you will find.

[jconley]

I'm building an ERA Cobra, and initially I was think of using a 428 because it was used in the "street" version of the Cobra, plus because of it's reputation for high torque at low rom. My car will mostly be used for cruising, with some autocross, and may be a track day. So, I'm not necessarily looking for high HP numbers, but a car that is easy to drive on the street and highways, and with low end torque for autocross (60 mph max).

I was reading the book Shelby Cobra Fifty Years, and learned that there were actually "street" 427s (CSX3301 and later). So I was curious if there was a resource (book, web) that described the difference between the three 427 engines.

Heads and intakes: low, medium and high risers
1x4, 2x4 carburation
compression ratios
cams
etc

Perhaps there are too many differences to list, and I can understand that. I suppose the fact is that a 427 can be configured with the right components to be as streetable as a 428.

[patrickt]

Originally Posted by ACademic

I think the OP might be interested with the internal differences, i.e. compression ratios, camshaft profiles, etc. I'm pretty certain the full competition engines were running at least 12:1 compression and perhaps as high as 14:1. Would be interesting to see a comparison of the actual compression and cam specs for comp vs. S/C (to see how much Carroll had to detune the cars to sell them as "street" runners).

I have a book that has that -- and it's reasonably believable, not just made up. There were several configurations, as I recall. But remember, back then you could get Sunoco 260, with the little "Dial-a-Pump." I use a cam that is actually a clone of a cam that was swapped in by CS for several of the engines that were a step below what you might call full race. But Lykins will tell you that cam architecture has come a long way in 50 years, but it's what I wanted. The OP could easily build an engine that is, for the most part, pretty similar to what they were 50 years ago. He just needs to sit down with a builder that is familiar with what was being done back then, because gas has changed. He's probably better off just instructing his builder as to what his goals are, as opposed to telling him what specs he wants for the internals. I did that, and my builder decided to go with an original spec'd cam from "back in the day." Had Lykins built my engine, I would have had to of twisted his arm to do that. But, who knows, maybe Lykins would have been right and I would have liked his choice more?