452 heads

[the nitro man]

i'm working on a 451 & i'm thinking of using a set of 452 heads with stock sized valves along with a set of KB215 or KB251 pistons. i'm thinking of doing some template porting, & a little short side radius work to them (very little), & a valve job. what kind of power could this set up make on a 451? what size valves are the mopar templates for?

if i could afford rpm or stealth heads that's what i would buy, but i can't right now, so i'm thinking of the 452's. i'm wanting to make around 500 hp & have great torque as well. thanks

[Nacho-RT74]

mopar templates are for stock 2.08/1.74 valves 3/8" steems ( 915, 906, 346, 452, and even some MP heads )

a mill down job will help a liitle bit more, try to get 84cc at least from the original 88-92 cc they are from cast

[Rayzor]

I think you would be better off having oversized 2.14 1.81 valves put in and then having them cut with a bowl cutter. Then you just blend the guides in a bit and some minor clean up and you will do better then the template port job. Alot less grinding work to.

[Nacho-RT74]

won't have sense then to have 452s, because deals on these are the hardened valve seats without need of anything. Would preffer to cut 915s or 906s

unless hardened surface is thick enough ?

[Rayzor]

I have found the area around the intake valve is wide enough to take the 2.14 valve without getting away from the hardening. You can see this area as a small depression circling the valve. I have always gone with the newer exhaust seat anyway though. as a bonus you can turn up valves with the 11/32 stem and that can also help flow. Yes it will add to the costs, but if 500 horse is the goal its going to need air in and out. Not saying it cant be done just sharing a opinion.

[the nitro man]

well i've got a set of bare 452's on the way here. they are being opened up for 2.14-1.81 valves, 75 degree bowl cut, cut for larger springs & positive valve seals, with hardened exhaust seats & new guides installed for $256.00 shipped. that's with him furnishing the heads.

all that should be left is blending the bowls, & cutting the guides down.

[Nacho-RT74]

Rayzor...are you SURE about the hardening deal on 452 is enough to still fit 2.14/1.84 valves and still be on the hardened area ? is that for real?

then can be ported first and then cut for the new size ?

How deep is the cut ? just to fit the bigger valve ?

Sorry the highjack

[Rayzor]

Your moving the seat outward from the original cut so your not going any deeper there. And yes there is enough meat around the valve.  But not always, sometimes with worn guides and seats that have worn in they can be to far gone to take a fresh cut. when the seat wears and guides are sloppy the valve will rock side to side wrecking your chance at just cutting a new larger seat so new seats are needed. I have always done the bowl cut after the new seat cut is in and use it for a guide for the bowl cutter.  If you do it that way then your basicly left with a little shape work around the guide and blending in the bottom of the bowl. By the way, when you get your new valves have them back cut a hair. Really helps flow around the valve.

[Nacho-RT74]

well I know there is enough meat around but wasn't sure if hardened meat.

yeah, 30 degrees cut on valves, I have read about, but still needing info about where to cut or not. I'm going first with porting templates, and then will think if get bigger valves or not and all the extra job required... on that moment will decide if go with or not.

I also have read about some seats angle mods, but not clear about yet

I guess I should make the porting first and then the bigger valve cuts... right ?

[Rayzor]

The porting should be done after the seat cuts are in. That way you can blend into the seat. Even if your not going oversize a bowl cutter run down until its almost to the valve seat will save you hours of grinding and it will almost mirror the template work in the bowl.