10141279...96-up...oval..CLOSED.."Vortec 7400", 100cc chambersHead Casting # 10141279 They Came Of A 10hr 2000 Merc Mpi Engine As Far As I Can Tell They Are Identical To The Vortec 7400 Heads
I had the same heads, from a ZZ502 on my 540, it pulled to 6200 on a B impeller. I would suggest having the valve guides checked, as they run a bit tight for marine use. I upgraded to Inconel exhaust valves before I ever ran them. I put 8 seasons on them, never has an issue, no evidence of corossion in the water passages. I sent them out for rework this year, I opened them up to rectangle port, easy to do, lots of metal to allow this. I then sent them out for valve job, and flowing. got a call from the flow guy, and asked why I stopped on the port job, I said I never felt comfortable going any further. They said they could make even for improvement dropping in from the pockets, and again opening up the runners. I told them have at it, said I wanted the most out of them. I wound up with 2.30 intakes up from 2.25, with 1.88 exhaust. The flow numbers on a 4.25" sleeve were excellent, 395 int. and 292 ex. still with great velocity in the runner. I will find out what thy do next season. Here is a before and after of the rectangle port match, but I don't have any pictures taken since the flow work.I am building a zz502 for my jet boat and I have a set of 454 mpi heads does any body know if these heads will support a 6000 rpm motor
Well, in digging arround the web, I find SOME references that connect that head as the "L29" head, which was a truck headquote]
Thats pretty much what I gathered at the time. The L-29 is what I remember them being refrenced as. It's about time some flowed a set.