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turbo2256
09-12-2002, 12:48 PM
Guess this is mostly for Big Grizz....In your 351C did you put oil restricters in the oil passages. I have in the past but taking it a step further after looking at the front cross drilling.

BigGrizzly
09-12-2002, 06:11 PM
No,I did not use oil restrictors, The Clevland had a valve guide problem, I wanted as much oil up there as possible. The returns are so largenot much staied up there anyway. I was more concerened with the cooling. People have of removing the water pasage restricter under the thermostat for cleaning and not replaceing them. I've had no oiling problems. I do use rollar rockers,because of valve guide wear, not for speed. This pretty much ends the valve guide problem.

Randy

turbo2256
09-17-2002, 09:55 AM
The restricter under the thermostat is the bypass it is plugged by the pellet on the thermostat when it opens. dont loose it they are not available any more. If lost I plug that opening use a normal sbf thermostat with a small hole in it to provide some flow. If the bypass is left open up to 20 percent of the hot water is reciculated back into the engine. I restrict or eliminate bypass hoses on most of my engines to increase cooling.

Never have had guide problems untill this guy brought in a Pantera(car) to work on had sucked 4 valve guides through the engine one of which fell out of the header as I removed it from the car but after looking at other parts of the engine... had to pitch heads block rods pistons saved the crank ... real hard to find "C" motors and aftermarket parts for them now.

BigGrizzly
09-17-2002, 01:17 PM
The real problem on the head is there so many. V4-open,V4 closed chambered (all big port heads) V2 heade-two styles of these than 351 m heads- slightly different casting and almost identical to the V2 heads and the Australian heads which are closed chambered V2 heads then the Holman&Moody marine heads which were big V 4 ports and V2 valves. I have collected and have all of them, because of the reason you stated. My 1971 MACH I is the V4, but put on V2 heads for a daily driver(kept the old V4 for and o4rigional engine for matching numbers). Valve guide is a real problem, especially when somone replaces a cam and doesn't get the rocker arm geometry correct. This really shows up with the stock rocker ratio of 1.73:1 -espcially if they twist the engine tight. The roller rockers eliminat this problem. The other problem is with that engine too much oil up there can cause valve float at high RPMS. It really pumps alot of oil up top. Origional designed for sled rokers. That engine will run 7,000 easily if camed corectly! the engine needs a dual profile cam to work well he cams that COMP Cams suggest are the worst I have ever used in that engine. I have 8 different grinds for the Clevlands and the Comp was so bad- in comparison I sent it back- been waiting for the money for 5 years now. On the other hand they have some good stuff for 350 Chevy motors. Eldbroc is talking about maling heads, but they have been saying that for 5 years too. If in a pinch what I have found works well is 351 M heads with the V4 size (2.15) intake valves and exhaust. It will still twist up into the 7,000 range but has better mid-range and Idle. This is what I did to the Corsican and the MACH I. The oonly problem is the intake needs to be changed. I like the Weiland X-celerator best. Blocks are a little tough, However the 2 bolt mains easily convert to 4 bolt style. I parked the 4 bolt block also. No need in my applications to use them, saving them too. God I'm saving a lot of stuff. No wonder my wife is mad at the basement

turbo2256
09-17-2002, 02:06 PM
I found a source for Aussi C blocks heads etc and bolt on aluminum heads from them as well ... back in the early 70s I ran an Aussi nascar block and heads in a 69 Shelby Mustang over 650 HP on dino shifted at 9000 RPM a daily driver at that time made quit a few bucks off Palm Beach elete in there "Exotic" cars.
Oh yea almost forgot the valve train geometry between the exh and int is different and to be exact need different rocker arms to be perfect one company in Fla makes them that I know of.

BigGrizzly
09-18-2002, 07:02 AM
Cool, never got that involved racing that engine. When working with Erson, I found how critical the rocker geometry was with thoes canted valves. Every time there was a valve problem that where it stemed from not that its a great design but I really do like the Clevland and what it can do. Especially for an ancient piece.