351C 2v 103.4mph and 13.9sec (a bit long)
1971 Merc Cougar XR7, 3800lbs with me in it. Been working and fine tuning this engine build for almost 2 years. This is a real fun street machine that I drive every day. Can smoke'em any where and she revs to 6000rpm. She shifts at 5000 rpm in auto or I shift at 5500 rpm in manual. If you ask how fast it'll do? At least the speed limit.
A bit of a story before the stats. The reason for the lengthy story is I want to show that very good performance # can be achieved with the right combination and patience. Sure I wanted everything to fall in place the 1st time. It just didn't. I kept working at it.
I origninally chose a cam with specs of 212/216 dur @.050, lift .498/.510, 110 cntr. It wasn't enough performance for me. Dyno Jet chassis dyno 220hp and 270tq. I then choose a new cam 222/226 dur @.050, lift of .531/.531, 108 cntr. The cam company said to install it at 110 for better low end tq. This completed I ran 160hp and 231tq. Yes, you read that right. Everything went down drastically. I changed intakes, carb , fuel lines, fuel pump, converted to electric fans. Several months later I went to a new local Mustang Chassis Dyno and ran a 180 hp and 210tq. So had to rethink everything and finally cam to the conclusion that the drop in hp/tq came after the cam change. Duuhhh! I did install it at the recommended 110 cntr. But the cam was ground for 108. So I pulled everything apart and installed the cam straight up, as designed. 250hp and 285tq on a Mustang Dyno (25% driveline losses give me 330hp/380tq at the flywheel)! Ahhh. The Dyno operators say a Mustang Dyno gives lower numbers than Dyno Jet dyno because Mustang Dynos factor in vehicle weight as a load. Dyno Jet does not. I need to return to the shop where I did the 1st Dyno Jet baseline runs. To confirm this. I have purchased a G-Tech meter and have run best mph and time of 103.4mph/13.9sec.
351C .030 over
c/r 9.1-9.4:1, ARP rod bolts
2v heads - Stock sizes, porting behind bowl, stainless steel valves, single groove locks with new retainers
Crane Roller fulcrum conversion
Windage Tray
4MA crank
Comp Cam camshaft #32-309-4 with matching valve springs
Weiand Xcerator intake
Holley 3310 carb with Proform main body
Holley Red electric fuel pump
1/2" fuel line
Hooker Heads
3" collectors
"H" pipe
2.5 mandrel bent exhaust
Flow master 50 series mufflers
FMX transmission
B&M break away torque converter
9" rear end with Powertrax unit
3.5:1 gears
Battery relocated to trunk
Electric fan with custom fan shroud
Custom sub frame connectors
Lakewood traction bars
Custom ram air
1968 Merc Cougar, 302 Street Boss (302/351C 2v heads)
1971 Merc Cougar XR7, 351C 2v
on edit, title changed, - blizz