IQ52
Well-Known Member
Understand from the get-go, this isn't a high performance 400 B engine build. This is what the customer wanted for his '72 Dodge pickup. Lots of things could have been done differently. But with the instructions, "My employees will be driving this truck, I don't want anything wild," we settled on a 7.5:1 compression, 85 octane, 2bbl rebuild.
Decked and then bored +.030" and honed with a torque plate.
Stock replacement cast pistons.
The stock 1972 2bbl holley and stock 2bbl cast iron intake.
We fudged some with the cylinder heads. 346 heads with hard exhaust seats, 2.14/1.81 valves and flowing.
Lift.............INT/EXH
.100............85/58
.200..........164/120
.300..........217/168
.400..........234/198
.500..........253/212
Camshaft is the Summit 6400, 214/224 @ .050, 444"/466" @ 1.5:1
New, take off, 440 Source valve springs set at 120# seat, 240# @ .450" lift
Comp 10 degree retainers and locks.
Standard Sealed Power oil pump 45 psi hot oil pressure at 750 rpm idle and 75 psi @ 5200 rpm.
Stock 1972 400 distributor recurved. 18 degrees initial 37 degrees total @ 2500 rpm.
And used our dyno headers.
We dyno'd it with the 2bbl carb and intake and then switched to a 383 Holley Street Dominator and a Quick Fuel Q950. What follows are the results.
RPM................2BBL TQ/HP................4BBL TQ/HP
2500....................351/167.....................337/160
2600....................350/173.....................334/165
2700....................355/183.....................325/167
2800....................367/195.....................325/173
2900....................371/205.....................337/186
3000....................368/210.....................359/205
3100....................369/218.....................379/224
3200....................366/223.....................381/232
3300....................367/231.....................389/245
3400....................361/234.....................399/258
3500....................359/239.....................400/267
3600....................360/247.....................399/274
3700....................354/249.....................399/281
3800....................351/254.....................402/291
3900....................343/255.....................403/299
4000....................337/256.....................401/306
4100....................329/257.....................401/313
4200....................325/260.....................398/318
4300....................326/267.....................397/325
4400....................323/270.....................396/332
4500....................322/276.....................383.328
4600....................307/269.....................381/334
4700....................318/285.....................386/345
4800....................308/281.....................383/350
4900....................302/281.....................375/349
5000....................297/283.....................370/352
Made a backup run with the 4BBL and it made 397 LB-FT @ 3600 rpm and 361 HP @ 5100 rpm.
Ahhh, 7.515:1 compression? Yep!
Not too bad considering that the 10:1 HP383 was listed at 335 horsepower and the 10:1 HP440 engine was listed at 375 horsepower.
Now we put the 2BBL back on and the customer can install the 400 in his truck.
Decked and then bored +.030" and honed with a torque plate.
Stock replacement cast pistons.
The stock 1972 2bbl holley and stock 2bbl cast iron intake.
We fudged some with the cylinder heads. 346 heads with hard exhaust seats, 2.14/1.81 valves and flowing.
Lift.............INT/EXH
.100............85/58
.200..........164/120
.300..........217/168
.400..........234/198
.500..........253/212
Camshaft is the Summit 6400, 214/224 @ .050, 444"/466" @ 1.5:1
New, take off, 440 Source valve springs set at 120# seat, 240# @ .450" lift
Comp 10 degree retainers and locks.
Standard Sealed Power oil pump 45 psi hot oil pressure at 750 rpm idle and 75 psi @ 5200 rpm.
Stock 1972 400 distributor recurved. 18 degrees initial 37 degrees total @ 2500 rpm.
And used our dyno headers.
We dyno'd it with the 2bbl carb and intake and then switched to a 383 Holley Street Dominator and a Quick Fuel Q950. What follows are the results.
RPM................2BBL TQ/HP................4BBL TQ/HP
2500....................351/167.....................337/160
2600....................350/173.....................334/165
2700....................355/183.....................325/167
2800....................367/195.....................325/173
2900....................371/205.....................337/186
3000....................368/210.....................359/205
3100....................369/218.....................379/224
3200....................366/223.....................381/232
3300....................367/231.....................389/245
3400....................361/234.....................399/258
3500....................359/239.....................400/267
3600....................360/247.....................399/274
3700....................354/249.....................399/281
3800....................351/254.....................402/291
3900....................343/255.....................403/299
4000....................337/256.....................401/306
4100....................329/257.....................401/313
4200....................325/260.....................398/318
4300....................326/267.....................397/325
4400....................323/270.....................396/332
4500....................322/276.....................383.328
4600....................307/269.....................381/334
4700....................318/285.....................386/345
4800....................308/281.....................383/350
4900....................302/281.....................375/349
5000....................297/283.....................370/352
Made a backup run with the 4BBL and it made 397 LB-FT @ 3600 rpm and 361 HP @ 5100 rpm.
Ahhh, 7.515:1 compression? Yep!
Not too bad considering that the 10:1 HP383 was listed at 335 horsepower and the 10:1 HP440 engine was listed at 375 horsepower.
Now we put the 2BBL back on and the customer can install the 400 in his truck.
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