Short runner Cathedral MSD

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Mar 30, 2025 | 09:23 AM

raymond mckinney

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From: Tampa, FL

Short runner Cathedral MSD

Swapping to Mast 295 heads on my 427.
Thinking about trying to shorten the MSD runner's.
Has anyone tried this? I know it works on LS7 units.
The runners are 8.7 stock i believe. Id probably buy another manifold and compare it to a fully ported standard runner.

Mar 30, 2025 | 05:50 PM

jhshnh

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I’ve often wondered what a dyno comparison would look like shortening an MSD runner. I have a Mamo ported MSD, so I’m interested in results.

Apr 2, 2025 | 11:01 AM

kinglt-1

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Might be more cost effective to sell the MSD and go with a BTR Trinity. RPM recently did a back to back test and the BTR made quite bit more power with the BTR over MSD. I believe it was over +40whp gain.

Apr 2, 2025 | 07:45 PM

wannafbody

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But aluminum heat sinks.

Apr 2, 2025 | 07:51 PM

G Atsma

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Quote:

Originally Posted by wannafbody

But aluminum heat sinks.

I still remember that argument from when the early cast aluminum manifolds came out.
What were the claims on HP losses due to the extra heat?

Apr 2, 2025 | 07:51 PM

raymond mckinney

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Quote:

Originally Posted by wannafbody

But aluminum heat sinks.

Plus they are heavy.

Apr 2, 2025 | 07:53 PM

raymond mckinney

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Quote:

Originally Posted by kinglt-1

Cathedral vs LS7 not sure it would gave the same

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Apr 3, 2025 | 07:51 AM

kinglt-1

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I would assume with those 295 heads and 427 cubes it would yield similar results. It seems like the large cube motors like that manifold.

Quote:

Originally Posted by wannafbody

But aluminum heat sinks.

The air moving through the manifold has little time to heat up.

They are heavier if you are worried about 5lbs.

I have a 90lb aluminum heat sink on the top of my engine. It runs cool enough to keep all the timing in it after several hard pulls.

Last edited by kinglt-1; Apr 3, 2025 at 07:57 AM.