This is a fantastic video showing how it is done the right way. I use slightly different cutters and some similar. Practically speaking last month I bought two brand new rectangular port Mark IV aluminum heads with bronze valve guides shipped for $450. A new set of stainless steel valves, retainers, shims, valve seats, and keepers for $350, plus the matched springs for my 0.670” lift roller cam for $200. The heads needed a few minutes with a die grinder and the valve seats trued up with the die cutters for the 3 angle seats that were already cut with the new heads. Assembled new in-house a pair of aluminum Chevy large rectangular port heads for about $1000 brand new. Practically speaking this was inexpensive and less time consuming. I did cc the chambers and checked the ports which where had minor cleanup. Unfortunately I don’t have a flow bench but these heads support a 600+ horsepower Chevy 454 stroked to 482 cubic inches. One day I will have a flow bench and get to the next level. This video is an excellent reference but hope one does not have to do all this machining each time, but just as needed. Cutters for spring seats, guide heights and performance seals are inexpensive and readily available.
i feel like Mark needs to just let Tommy film. every video he asks "are ya getting this?" "no Mark im fucking a saw horse right now. Yes im getting this" says Tommy probably.
@Hugh O'Brien I’ve read that the gains are only beneficial in above 6K rpm situations. In which case, it can be a 100 hp gain. But there’s plenty of 450-500 hp 396’s that peak before 6K rpm. 460 being most likely- 500 the standout. I’ve got a set of 702’s for my 402. I’ve clearances .230” around the valves. That should be plenty for stock valve sizes. Plus followed marks instructions and wideent the exhaust port floors and left the port roof alone. I also did a “bowl job” while trying not to get the throats too big. I’m 1.91 right under the seat. I realize that’s kinda big but it’s the factory knurled throat size so I don’t think it’s too much. I’m an auto tech by trade but don’t do much porting. Marks videos have really helped.
Nice work I have a 496 im building I also have a set of 1974 781 castings id like to shoot for more hp on race gas can you give them this treatment ? maybe some 2.25 or 2.3 intake valves I like your attention to detail !
You do not even give the guy with the camera half a second to re position the camera and get it focused. No wonder he is all over the place with it and never has the work centered. You need to slow down just a bit when your filming. The camera man needs time to get centered on the work and the camera needs time to focus.
