tbirdscwd

I would trust Tim and Andy at MPH over just about anyone when it comes to building modular motors. They built me one helluva nice one

mrtstang

Yeah, MPH was very nice to me, but even they weren't aware of some of these ptv clearance issues that we're talking about here.

Check out Modular Head Shop, and see what i mean. I'm starting to see, more and more, that Nick's findings are being are being realized and supported by others. Even John Tymensky (the man who basically designed the mod motor, and is arguably the best modular engine builder in the country) supports these findings.

nickmckinney

On many engines it is the exhaust valve that is the problem, the PI is the only modern inline valve engine I know that has the intake valve 0.1" closer to the piston than the exhaust valve. That 0.1" is a deal breaker and going to an aftermarket valve still leaves it 0.060" closer than the exhaust valve. Both the NPI and SVO head do not have this issue.

IMHO Comp is clueless for the PI head, after 11 years they still spec springs for a PI head with the NPI specs (again 0.1" difference which is huge also on valve springs) You install their recommended 26113 spring in a PI head you might as well leave the stock spring in there as its no different.

Now ask me about good cam specs for a LT1 or LS1 and I am clueless

nickmckinney

To be honest I find most shops building nice motors don't even think about it as they are usually replacing the pistons with a forged notched version which solves the problem properly. Its really only the NA stock motor crowd that are hitting the wall which is why the 2V gets a lot of the bad rap (a stock PI motor NA you can only do so much without notching the piston, blown or turbo you can cheat it a bit)

tbirdscwd

Yeah, I doub't most high end engine builders really do see this as an issue since, like you said, they are almost always going with an aftermarket forged piston anyways.

mvr

i guess il talk to the shop im going to go to for the install and see what they say about installing these cams. the shop manager is in the local mustang club, its basically the best shop domestic speed shop in vegas. he has an insane 03 cobra vert, he had his shop do all his motor work.

WannaBeGearHead

To help with install costs, Nick at MHS sells matching cam gears. Seems like a good way to save on install costs.