My rebuild to increase C/R and bigger cam

65-coupe

Well-known member
Well I deiced to rebuild my bottom end to raise C/R and went with a bigger cam. Before the rebuild I had a stock bottom end, Alum head and intake, 1.65 roller rockers, 264/264 110 cam(advanced to 106), Holley 390cfm 4bbl, DUI and headers with x pipe and 2" exhaust. I had another block zero decked and installed flat top pistons. I also switched to a 274/274 110 cam, Advanced to 108 after talking with Clay Smith Tech. C/R went from 8.5 to 10.6. Car runs better to sure how much yet. Going to dyno in a few weeks after I put some miles on the car and install MSD Atomic EFI. What is odd to me is the car is not as loud now. It is a lower tone and smoother sounding. Also Mustang Monthly is following again.




 

XMFalcon221

Well-known member
Looking forward to the dyno results, did you do any dyno runs with the previous build? Would be interesting to see a comparison

What type of carb air intake hat is that in your second photo?
 

xctasy

5K+
VIP
65-coupe":2zj89qk8 said:
.........C/R went from 8.5 to 10.6. Car runs better to sure how much yet. Going to dyno in a few weeks after I put some miles on the car and install MSD Atomic EFI. What is odd to me is the car is not as loud now. It is a lower tone and smoother sounding.....

Gotta love your work, sounds like a real treat!

High compression ratio cars with flat tops and nicely timed cam to suit the the compression does that. Mechanically, its not working as hard, and yet it produces more power and torque. As has been said, some engines leave a lot of performance, smoothness and off idle spark when the cams are small. One guy said that even on an emission/economy ohv engine, to use less than 270 degrees of cam duration is a waste. I've said that too. One guy said that having less than 1.3 hp per cube was liking drinking wine form a paper cup.

80 hp per liter has been done by one person here with a 480 cfm 3.3 and Classic Inlines head, seams like people are finding Aussie style specfic outputs don't incur a driveablity or tractabilty loss in T5 applications....


My 250 Alloy Head II X-flow with 252 Heatseaker cam, headers and 500 2-bbl on 9.7:1 compression making about 170 hp was quieter than my 92 hp 200 8.9:1 small log headed Mustang with 256 cam, dual pipes and 1-bbl.


My wife keeps telling me that the 3.3 81 Fox sounds just like an engine with twice the power, but it drives like an emasculated Pinto....
 

65-coupe

Well-known member
XMFalcon221":3cr6bfa2 said:
Looking forward to the dyno results, did you do any dyno runs with the previous build? Would be interesting to see a comparison

What type of carb air intake hat is that in your second photo?

We did a dyno run before before the alum head and after about a year and a half ago. The air intake is from Spectra and I painted it black with VHT crinkle paint.

http://www.mustangandfords.com/how-to/e ... r-engines/

I can not find the article after we installed the T%. But it gained another 10 RWHP and 15 RWTQ
 

65-coupe

Well-known member
I never did update this from three years ago. Sorry about that. The engine did well even though the number 6 piston cracked between the top two rings. It was about a 2" wide. Plus the rings did not seal properly. So I had lots of blow by. We dyno the car after I drove it about 800 miles on the new short block. lots of white smoke came out of the breathers. The car made 166 RWHP and 185 RWTQ. So I am guessing it would have been 10-20 more HP and TQ if rings sealed better and the piston was not cracked. So it should have been about 200 crank HP if you figure 20% loss.

Now I am building a 250 hopefully have it installed soon.

Cheers Brian
 
Top