60sMustang
Well-known member
pedal2themetal45":hrukrstb said:
I agree, i'm going .040 over actually. The machine shop did not think .030 over would be enough, so we went .040 to be sure.
Bore + Cam selection - rebuilding a 200 I6
- Thread starter 60sMustang
- Start date
I agree, i'm going .040 over actually. The machine shop did not think .030 over would be enough, so we went .040 to be sure.
Howdy 60'Mustang:
I'm late to this party but thought about it and couldn't sit out. ON the overbore, cylinder walll flex becomes more of a problem as the bore increases. That and production control on these engines can lead to thin bores to begin with. .040" should not be a problem but .060" and over should be proceeded by some sonic testing for wall thickness.
On the cam, what will be your typical use for this engine? Rpm range? For most street engines with an occasional burst of enthusiasm, any of these cams are a great improvement over stock. With a stock head and valve train any lift over .400" is of little value, especially with a one barrel carb. IIWIYS, I'd be looking at something in the 256 duration range to enjoy a little more bottom and mid range. A cam in this range will still be a smile maker over a stock cam. Lobe profile is the difference.
Keep us posted on your progress.
Adios, David
I'm late to this party but thought about it and couldn't sit out. ON the overbore, cylinder walll flex becomes more of a problem as the bore increases. That and production control on these engines can lead to thin bores to begin with. .040" should not be a problem but .060" and over should be proceeded by some sonic testing for wall thickness.
On the cam, what will be your typical use for this engine? Rpm range? For most street engines with an occasional burst of enthusiasm, any of these cams are a great improvement over stock. With a stock head and valve train any lift over .400" is of little value, especially with a one barrel carb. IIWIYS, I'd be looking at something in the 256 duration range to enjoy a little more bottom and mid range. A cam in this range will still be a smile maker over a stock cam. Lobe profile is the difference.
Keep us posted on your progress.
Adios, David
60sMustang
Well-known member
CZLN6":2qvvccpo said:
I decided on the Howard's Cams 267/267 - 110. The builder just finished an engine exactly like mine and I was able to see it run with this setup. Didn't see any reason to switch, since my original plan was the Comp Cams 260H - 110. The number are almost the same at .050 and he had good luck with the Howard's in that build. I also thought the same, about most performing the same for my intended use, just had to pick one. Seeing it run in an identical engine was helpful.
I think between the Cam, .040 bore, port and valve work I should see a noticeable difference. Also doing the T5 conversion while I have it torn down, so that should increase the fun factor as well.
Gene Fiore
Famous Member
Should run good!
60sMustang
Well-known member
rbohm":pf7xjo7h said:
Thanks. About the time its done we will be in snow season here, so I wont really see the results until spring. This gives me plenty of time to take my time and put it all back together nice and neat.
60sMustang
Well-known member
Gene Fiore":8z3sfvzq said:
Fingers crossed, I'm thinking it should be like driving a whole new car with the extra HP and the T5.
60sMustang
Well-known member
rbohm":qyjc6nqm said:
I'm not one to run high RPM's often, so I wanted a cam that was a low-mid range performer. Then the additional 2 forward gears should make it cruise a lot nicer also. With the setup I have planned and use I just described, do you have a recommendation on rear end gears. Don't get me wrong I want it to go...just not one to abuse a car though.
60sMustang
Well-known member
chad":2rdtzgad said:
225/60/15's on the rear
mostly 2 lane roads 55 MPH speed limit
Some stop and go but not city driving, no baby carrying...but no racing either.
Just want a mid range gear that performs well low to mid range with the cam and also can run out a 65 with no problem.
60sMustang
Well-known member
wsa111":u75z0fm2 said:
How would I determine which differential and gears are in it currently. I'm thinking it may have been changed before I got the car, since the speedo is off by about 10 MPH(reads higher than your actual speed, at about 50 MPH shows about 60)
I was considering jacking up the rear end and turning the drive shaft to see how many times it takes for the tires to make a full revolution. Any other methods to figure out what I have in it? Also how do I tell 8" or 9" rear end? Are the number of bolts different?
1 way on the gear ratio is:
Jack up one tire so other doesn't spin (locker?).
Rotate DS 2x, watch & count # of tire rotations.
Divide that number into 1, multiply that number by 4.
That's ur gear ratio. Look to accuracy by comparing to known ratios.
Try to get as much accuracy on the tire rotation (it will not be a whole number - .33?, ,25?, etc) for your 1st equation.
I know less about the 8 inch rears so I PM you on that.
Jack up one tire so other doesn't spin (locker?).
Rotate DS 2x, watch & count # of tire rotations.
Divide that number into 1, multiply that number by 4.
That's ur gear ratio. Look to accuracy by comparing to known ratios.
Try to get as much accuracy on the tire rotation (it will not be a whole number - .33?, ,25?, etc) for your 1st equation.
I know less about the 8 inch rears so I PM you on that.
Gene Fiore
Famous Member
Isn't that the other way around?Econoline":2p1127hg said:
60sMustang
Well-known member
wsa111":32vnwq8d said:
I think I've determined its a 3.20:1 in the std 7.25" rear end. I may just leave it at that until I'm ready to upgrade to 8".
"gene is right, its the other way around."
yes the 2 bottom on the nine need open end wrench
also the top of the nine (chunk itself/ the center section) is rounder, the eight has a flatter (less arched pinnacle on chunk housing) in side view.
yes the 2 bottom on the nine need open end wrench
also the top of the nine (chunk itself/ the center section) is rounder, the eight has a flatter (less arched pinnacle on chunk housing) in side view.
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