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mggdoors 09-10-2019 01:17 AM


mggdoors 09-10-2019 01:22 AM

Just a heads up. First issue yesterday. Very last run of the day the crank driven water pump, Johnson F6B-9, the impeller cover came off. Screws backed out revealing the impeller and alot of water. Got drivers engine lil warm at 210 but still not crazy. Got to run the **** out of the bilge though. Did destroy 4 Alpine PDX amps on the back of the rear seat as well. Friendly reminder to check your crap. Happy boating.

mggdoors 11-18-2019 01:54 PM

Ok boys. Round 2 has commenced. Some updates first. On our original dyno run we had that flat spot that came in around 5200 and just killed power. We ran it for the season and then did some investigating after we repulled them. Turns out the ******* that did my cylinder heads did not shim the valve springs. Some (alot) of the seat pressure were in the 120 range. Can we say unstable? Now for the good stuff. While I have the heads off we are upgrading the lifters from ls7 to johnson short travel linkbars and manton 3/8 .130 custom pushrods, titanium retainers, and possibly yella terras in same ratio. The heads will be getting kissed to push compression from 10.6 to 11 and head porting will also be taking place. The shop doing the heads is claiming 360 cfm compared to 320 stock and only going up 10cc on port volume. Other minor details will be putting the std pressure oil spring in to reduce oil pressure from current 100. Dyno in month month and halfish. Place your bets. Here is previous dyno chart for referencehttps://cimg8.ibsrv.net/gimg/www.off...3f9d34882.jpeg

NautiSouth 11-18-2019 06:26 PM

120lbs on the seat isn't necessarily bad, if the valvespring frequency is on point. NASCAR engines of years past ran springs with seated pressures within ten pounds of that. I actually think it's in the right ballpark, if the rate and damping are appropriate.
PM me if you'd like to talk further on your valvetrain.

mggdoors 11-20-2019 05:02 PM

Slight change of plans. Ordered some zl1 superchargers, holley terminator efi, and having chambers on heads softened as well as everything previously listed. Aiming for 8psi to keep it simple.

mggdoors 11-20-2019 05:16 PM


Originally Posted by NautiSouth (Post 4715502)
120lbs on the seat isn't necessarily bad, if the valvespring frequency is on point. NASCAR engines of years past ran springs with seated pressures within ten pounds of that. I actually think it's in the right ballpark, if the rate and damping are appropriate.
PM me if you'd like to talk further on your valvetrain.

You may be correct but the stock springs are 120 and they can not control anything more aggressive than a stock cam for the most part. I personally believe its low for these heavy 2.165 valves. Now that the blowers are going on I definitely need to get the ducks in a row.

mggdoors 01-15-2020 03:08 PM

https://cimg8.ibsrv.net/gimg/www.off...beddd752c.jpeg
Zl1 superchargers being installed

Wildman_grafix 01-16-2020 05:56 AM


Originally Posted by mggdoors (Post 4721899)

Can those be used with a carb?

mggdoors 01-16-2020 10:33 AM


Originally Posted by Wildman_grafix (Post 4721961)
Can those be used with a carb?

No. An intercooler lid goes on top. These are efi only. I’m using Holley efi.

Wildman_grafix 01-16-2020 10:59 AM


Originally Posted by mggdoors (Post 4721996)
No. An intercooler lid goes on top. These are efi only. I’m using Holley efi.

That is what I thought, I have been looking at the LT-4SC direct injection motors and wondering why no one uses them. Seem to be they way to solve the loos in Cu In.

This should be interesting, keep posting.


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