Ultimate 6.5 Build

[Woody35]

P400 Block with concrete in lower cooling passages and girdle, pensuilar forged crankshaft, Mahle Monotherm steel pistons, custom forged rods, ported and polished heads with similar valvetrain to mikey von's and bored out precups. all topped off with inline injection pump, custom injectors, and a Holset HE351VE turbo.

only worries are the cylinder head staying attached to the block at 50 psi+, gasket staying one piece, block intergrity, and the price

 

[6.2 turbo]

I would want a bigger turbo,and a custom built twin disc clutch, and maybe add a 1/4 inch stroke to the crank,and a very custom solid roller cam,with adjustable rockers. And the p pump needs to put out fuel just like a cummins powered pulling truck this thing will surely have at least 1000 hp,all you need is money and time.

 

[buddy]

6.2 turbo thinks just like me Add the custom headers to the list. CIL6 really had something going there that has stalled for the mean time it seems.

I have a set of lifters that were modified by Rhoads to bleed down at low RPM and achieve max lift and duration around 3000rpm, to go with the custom cam profile I had ground. I wish some place would cut a billet cam, but they dont have the blank or whatever it is they need to do that, so would have to pay big bucks for it. Need to machine pistons with valve reliefs to make it all work. And some 1.6-1.7:1 adjustable ROLLER rockers for sure. Not sure I am brave enough for the stroking, but considered if I were to try putting one in a car, maybe like an 1/8" stroke in combination with some thicker head gaskets. What would work good is pistons with shorter compression height (pin higher in it). Can get custom .03" ground crankshafts and .03" undersized bearings.

Might as well just get a DMax with no emissions on it.

 

[Woody35]

yeah my dad wants me to get a reliable truck for college. my choices are Dmax or rebuild the 6.5. kinda want to take the money he would use to buy the dmax and build a custom 6.5. but im waiting on cil6's build and some other people to see how it would go. i dont want to go blindly into the machine shop and hope it all turns out right

 

[3500GMC]

Money, Time, and a shed full of spares...):h

 

[chevyinlinesix]

I am sorry that I have not updated in a long time guys. Funds are just not there right now, I am still going through with the build though, but am focused on other things right meow.

It sure seemed like there was enough room for another 1/4" of stroke, but then it is not really a 6.5 anymore. If you had a P400 block I would not be worried about block strength. I don't really believe in high boost, but rather as much airflow as possible (efficiency), but there's more than one way to build an engine

 

[Matt Bachand]

I agree about the high boost. Without the fuel to make it become efficient, its a drain on engine power to create that boost.

Sometimes less is more. Finding the sweetspot is key.

 

[Monarkman]

I am sorry that I have not updated in a long time guys. Funds are just not there right now, I am still going through with the build though, but am focused on other things right meow.

Excuse me, did you say meow?

Now why would I say meow?! Do I look like a little kitty cat to you boy, jumpin' around all nimbly bimbly!?

 

[Woody35]

personally if you retain idi setup and most of the block ill still think its a 6.5. a big block chevy is still a big block chevy whether it displaces 396 ci or 540ci.

 

[randomid25]

6.5L + .25" stroke = 6.9L 420ci. 6.2 + .25" stroke = 6.6L 404ci. I've been thinking about this recently. Wonder how much scat would charge for a stroker crank? Shorter rods would be in order as well adding to the cost of something like this.

 

[chevyinlinesix]

As far as I remember talking with Scat, they do not do custom crankshafts. I have gotten a few quotes for custom cranks, they are $5000 with whatever stroke you want up to 5" IIRC. Cheapest billet cranks I found were about $3200.

Custom pistons would be cheaper than custom rods. If you shorten the rods too much, it will create a lot of side loading of the cylinder walls either scuffing pistons, or with a 6.5 probably windowing the block. Custom pistons you just move the pin higher up in the piston, which also increases piston stability, therefore increasing longevity.

 

[randomid25]

Looks like i won't be running a stroker anytime soon.

 

[buddy]

SCAT doesnt customize them.

A simple stroke would be a .03" which is only 1/32" using available .03" undersized bearings, and .015" thicker 5 layer steel head gaskets from Cometic. Still several hundred dollars, like $350 to custom grind the crank and balance at a decent shop, new bearings arent cheap, and $300 for Cometic gaskets. Thats on top of the $380 cast SCAT crankshaft. With that invested you can get a standard forged steel crankshaft. The tech support at SCAT told me thier cast crank should be fine with .03" offset. Otherwise there are welding offset techniques that wont cut away any of the original journal, they weld more material onto the journal then grind it to the size and offset you need. Costs a few hundred more, but how you could get 1/8" reliably.

 

[randomid25]

With that invested you can get a standard forged steel crankshaft.

Are you talking about a stocker? While i've heard the p400 used a forged crank, I know that all the gm versions are cast iron cranks.

I wouldn't even bother with it unless it was enough stroke to illiminate the oversquare bore to stroke ratio in my engine.

 

[buddy]

You can buy the standard forged crank for like $900 I think from pennisular. Not stroked.

 

[randomid25]

Interesting. Thanks.

 

[sshewins]

I don't know if this has been covered earlier, but either way...If you were to coat the skirts with teflon, wouldn't that solve the piston slap issue? The hot rod semi's are doing this and claim to retrieve about 20 HP from internal friction loss, plus minimize the above mentioned slap. Kinda win win, but I'm not sure if it would apply here, let alone help any.

 

[chevyinlinesix]

Yup, coatings on the pistons are an absolute must in my books, but I like to go overkill. I don't think it would be enough to save from heavy side loads from a big stroke increase though.