BT,

Bowl porting refers to smoothing out the transition from the port itself to the valve bowl area. Usually there are some sharp casting lines in this area from the factory, which creates tubulence and reduces flow. Also, sometimes the bosses that support the valve guide are smoothed out and reduced somewhat.

Thanks Budman. Anyone have an estimate on what bowl porting, new valves and hardened seats should cost per set - complete including machine work?

Blue Thunder, these are some rough estimates.

bowl/pocket port $225-250 per set

install hardened seats $100 per set

install bronze guide liners $85 per set

3-angle valve job $125 per set

machine for springs $45 per set

machine for seals $45 per set

You may need to have other things done to the heads like having them "surfaced", degreased, assembled, etc. Plus the cost of new stainless steel valves, springs to match the cams, retainers/locks. You could very easily have about $1200-1350 or so in one set of heads. Take it to a well known machine shop who does PRECISION machine work and that does lots of this kind of stuff. A shop that has a GOOD reputation.

All good info. I might suggest having complete bronze guides put in instead of just liners. They last a lot longer and dont cost much more.

Wow!! Serious sticker shock Kaama. Would you say it is worth doing this instead of exhaust, or visa versa. They are seeming to cost close to the same. What did your cousin use for exhaust on the 461hp dyno motor? Sorry if I missed it somewhere.

I guess a good automotive machine shop would be a performance automotive shop? I have one of those I use. Other than that, I used to use a perf automotive machine shop owned by a guy that raced outboards. Any value in using him instead in you opinion, or is a head a head?

Thanks again,

BT

Blue Thunder,

Get ahold of "Maxx"---he's a member of this board and is the one who's cutting a Bravo One drive 2" shorter project. His name is John and he lives in your area and could help you out. He's a super nice guy! He could direct you to a good machine shop in your area that could do the work and probably get you a good deal.

My cousin is using the Gil manifolds for his engines. It's up to you as far as what you want to do first. You'll need a Gil exhaust system to let the engines breath better. Doing the head mods and adding cams will help your engines produce the power, but untill you add the better than stock exhaust system it won't really break loose. You'll probably see about 380hp to 400hp with your stock exhaust with those mods. Once you add a set of Gils (or comparable) you will be in the 425-440hp range or so and the Gils will increase your rpm as well by about 300rpm or so.

Get ahold of Maxx (John) he will be happy to help you get in touch with the right machine shop. 757-739-5796

Mark/KAAMA

You are a wealth of great info Kaama!! When I get the engines on stands and have my plan defined, I'll get in touch with Maxx.

So you think I can get about 100hp per motor with exhaust and engine mods? That would be sweet. Say maybe 600-700rpm? I have a line on some 26p B1s labbed that might really work if I get that much hp boost. Running mirage 25p now at 4700. Thanks again bro,

BT (Dave)

good work here is were I feel you have some of the most to gain. And it dose not take away from reliability. Charlie

Thanks Beerman...

BT