Aluminum 170CC Heads - Questions

[Custom40]

Hi,

I am building a 331 Stroker (10.25 CR, .542" Lift/286 duration Hyd Roller) for a 1940 Ford Hot Rod project and I have some questions about the DART aluminum heads:


1. The spec sheet says the exhaust port is raised .135" from stock. Is the exhaust header bolt centerline also raised from stock or is it in the stock location?

2. The spec sheet says the exhaust bolts are on 2.00" centers and the exhaust port is 1.340" wide. Those dimensions leave very little room for a header flange. Does DART provide a custom machining service that will place the header bolts on a 2.50" or 3.00" center?

Thanks for your help!

Andy

[Awesome Bill]

it is higher than stock that much. you will have plenty of sealing room for the headers and you should not use a gasket with everything new. Hi-temp silicon is what we use and have no problems as long as the header is flat. We machine finish those headers for out in house installs and to give a perfect sealing surface so our custom customers won't have header problems. The flanges on most headers are at best finished very very ruff.

[malihoochie]

170's on 331" motors work really well. The .135" raised port helps the exhaust flow, but does not interfere with any of the header brands we have tested. The sealing surface area is the same as any other aftermarket companys head with a standard header bolt (2 inch center to center) pattern.

[Awesome Bill]

the 2.0" bolt center is stock the 2½ and 3" are for race headers. The 3", not alot of headers out there for the combinations that can happen.