I haven't posted in awhile and thought I'd share this one as I found it quite interesting. This build was one of those situations where the customer sourced a pile of his own parts and had two other machine shops perform various jobs. As you can imagine this build was about 7 years in the making. I was the lucky guy earlier this winter tasked with finishing the machine work and assembly followed by a dyno session. Lucky me.
'67 340 block that was decked previously but rusted badly, finish honed .030" and decked further by me.
Ancient Mopar Performance cast flat tops that had to be milled .055" for -.010" deck clearance. Stock stroke crank that the thrust was machined .030" too wide by a shop that is long gone. We had to turn and balance a stock cast 318 crank to substitute. Stock floating rods done nicely by some other shop with missing piston pin clips. Old Edelbrock Performer hydraulic flat tappet cam, paired with a set of reconditioned but otherwise bone stock set of Magnum 318 heads springs, valves and all. All I did was disassemble and lube the dry valve stems. A Crosswind intake topped it off and it was put together. This engine went together well once we figured out what style of pan he needed.
Breakin on the dyno was uneventful with my known good QFT 600 vaccuum carb. The engine had such a mild personality I really didn't expect much over 300 hp and maybe 340 ft/lbs with 15" of 750 rpm idle vaccuum. This little sucker made just shy of 400 ft/lbs @ 3500 rpm (395 ft/lbs) and 331 HP @ 5100 rpm each and every pull. Oh and this was on Esso 87 pump fuel with about 2 gallons of Esso 91 later on when we ran out of 87. I will post up dyno sheets later. Magnum heads really are quite good when small displacements are used.
What a fantastic little 344.5 inch engine. Started at the touch of the starter button and repeated identically each and every time as mild engines tend to do-think GM crate here. As I get older I can see how this engine would bore most of you guys to death but it was a nice change for me. I also can't help but think that this engine could knock down 16-18 mpg's or better and truly drive anywhere anytime. Here's a pic off the dyno as I need to change out the high pressure/high volume oil pump. J.Rob
'67 340 block that was decked previously but rusted badly, finish honed .030" and decked further by me.
Ancient Mopar Performance cast flat tops that had to be milled .055" for -.010" deck clearance. Stock stroke crank that the thrust was machined .030" too wide by a shop that is long gone. We had to turn and balance a stock cast 318 crank to substitute. Stock floating rods done nicely by some other shop with missing piston pin clips. Old Edelbrock Performer hydraulic flat tappet cam, paired with a set of reconditioned but otherwise bone stock set of Magnum 318 heads springs, valves and all. All I did was disassemble and lube the dry valve stems. A Crosswind intake topped it off and it was put together. This engine went together well once we figured out what style of pan he needed.
Breakin on the dyno was uneventful with my known good QFT 600 vaccuum carb. The engine had such a mild personality I really didn't expect much over 300 hp and maybe 340 ft/lbs with 15" of 750 rpm idle vaccuum. This little sucker made just shy of 400 ft/lbs @ 3500 rpm (395 ft/lbs) and 331 HP @ 5100 rpm each and every pull. Oh and this was on Esso 87 pump fuel with about 2 gallons of Esso 91 later on when we ran out of 87. I will post up dyno sheets later. Magnum heads really are quite good when small displacements are used.
What a fantastic little 344.5 inch engine. Started at the touch of the starter button and repeated identically each and every time as mild engines tend to do-think GM crate here. As I get older I can see how this engine would bore most of you guys to death but it was a nice change for me. I also can't help but think that this engine could knock down 16-18 mpg's or better and truly drive anywhere anytime. Here's a pic off the dyno as I need to change out the high pressure/high volume oil pump. J.Rob
