Wasn't there a guy from some Pacific island on the forums running a built 7m in a drag car? I remember this guy posting that he was having problems with stuff breaking whenever he revved past 10,000rpm.
7m revability discussion
- Thread starter figgie
- Start date
After reading all of this, I wanna know something.
Ok we all know the 7m can rev with a built head or even stock.
My question is though... HOW FAST CAN IT REV in stock configuration VS 5m crank & long rods?
How much of a difference do you think we would see if some one used a 5m crank, long rods, and bored the engine out to be over square (bore bigger than stroke)?
Do you think it would be an instant spool response monster or a total lag monster?
Ok we all know the 7m can rev with a built head or even stock.
My question is though... HOW FAST CAN IT REV in stock configuration VS 5m crank & long rods?
How much of a difference do you think we would see if some one used a 5m crank, long rods, and bored the engine out to be over square (bore bigger than stroke)?
Do you think it would be an instant spool response monster or a total lag monster?
I believe the 5M stroke is 75mm so with the 7M's 83mm bore it would be well oversquare so no need to bore it.
So you end up with
Computed Engine Displacement (CID) is 149
Computed Engine Displacement (Litres) is 2.4
Computed Engine Displacement (CC) is 2434.8
Not sure how much harder you're going to have to rev just to make up the HP you lose .5 litre less of displacement.
<edit> ignore the above!
5M is 83mm bore and 85mm stroke
83x85
Computed Engine Displacement (CID) is 168
Computed Engine Displacement (Litres) is 2.8
Computed Engine Displacement (CC) is 2759.4
So you end up with
Computed Engine Displacement (CID) is 149
Computed Engine Displacement (Litres) is 2.4
Computed Engine Displacement (CC) is 2434.8
Not sure how much harder you're going to have to rev just to make up the HP you lose .5 litre less of displacement.
<edit> ignore the above!
5M is 83mm bore and 85mm stroke
83x85
Computed Engine Displacement (CID) is 168
Computed Engine Displacement (Litres) is 2.8
Computed Engine Displacement (CC) is 2759.4
Last edited:
How about the Ford 5.4 with its 3.53" bore and 4.1" stroke? The 2000 Cobra R made peak power at about 6200 or something. Cam timing, the shape and ports of the heads, and the manifold have more to do with rpm power range than bore and stroke. Bore and stroke affect peak numbers, not where they will occur.
5m is 83mm stroke you get a 2.8ltr square engine, and you cant use 7m rods as there would be no room for the rings!
http://www.geocities.com/MotorCity/Pit/9975/dataBySubject/GasolineEngines.html#M-series
soz me wrong 85 mm stroke
soz me wrong 85 mm stroke
Damn hard to find accurate non confusing info on the 5M! 
So to answer MDC's question nope you can't bore a 7M block to make it oversquare using a 5M crank ......
So to answer MDC's question nope you can't bore a 7M block to make it oversquare using a 5M crank ......
if you did go for a M series crank you can use the m-teu rods atleast! going to require a shitload of $$$$ spent on the head to make it last tho
way to much work.
Adjuster uses the crane big block chevy inner springs without issues. He is even on a stroked 7m
cost should not be to big an issue especially when dealing with chevy parts.
Adjuster uses the crane big block chevy inner springs without issues. He is even on a stroked 7m
cost should not be to big an issue especially when dealing with chevy parts.