340 Build

-

ateam

A motor can
Joined
May 22, 2010
Messages
264
Reaction score
3
Location
Winchester, CA.
To be bored + .060", yeah I know. Eddy heads, #60779, with mild port work. I have a Magnum Performer RPM intake. Can this be machined for the LA bolt angle ? Speed Pro forged/heavy pistons. K1 H-beam rods, std. length. Forged 318 crank. Considering Eddy's Performer RPM cam,(package design). They claim 417 hp. and 397 torque. Approx.2,400 lb. car, for street and slalom/road courses. R154 trans with 4:10 posi IRS, out back. Any positive suggestions, on this "budget" build, are appreciated. Tanks, ateam.
 
Wow, that's a very lite car. I don't think you can machine the magnum intake to fit an LA head for less than just buying a new intake and selling the Performer RPM intake.
 
Wow, that's a very lite car. I don't think you can machine the magnum intake to fit an LA head for less than just buying a new intake and selling the Performer RPM intake.
Well, the car is a Jensen Healey roadster, aka "Jensen Jackal". Jensen designed the car to take a small block V8, but then the oil embargo hit, circa 1975 ? I'm building this car as, what might have happened. They used Chrysler/Europe components frequently, as in Jensen Interceptor/ etc. I own a machine shop, so changing bolt hole and pad angle, not that big of a deal. I'm just asking if anyone has done it. Thanks, Art.
 
I don't recall anyone drilling the intake. I think there's no area for a new spot facing for the bolt head... Everyone just drilled and tapped the heads to fit the LA intake. Is that R154 the Nissan 5sp transmission?
 
I don't recall anyone drilling the intake. I think there's no area for a new spot facing for the bolt head... Everyone just drilled and tapped the heads to fit the LA intake. Is that R154 the Nissan 5sp transmission?
Toyota Turbo Supra, called AX15 when used in Dodge Dakota trucks,(different ratios). Using Dakota V6 BH for direct fit to 340.
 
Why not just go with an LD340, Air Gap, or Wiand stealth intake that's made for the LA heads???
 
Then yeah, I've heard of people drilling intakes and heads for Magnum bolt pattern. Don't recall hearing of Magnum bolt intake being drilled for LAs.
 
Interesting combo with the trans and a great car. I passed one up some years back; that woulda been cool but no time to build it.

I would relook at the cam IMHO, and look to get something a bit torquier, not for the torque per se, but to widen the torque curve as much as possible for the road courses. And 1.6 ratio rockers would help that with a better lift vs duration ratio.

Any chance of going with lighter pistons to take out some of the mass? It'll help it to rev a bit faster, and that will show up readily in that light car. Plus take some stress off of the crank, which I would consider important the way this thing is likely going to be revved a lot. You would get a bit more weight off of the rods with I beams and be just fine for strength, IMHO. With the lighter rods and/or pistons, the re-balance would be a simple matter of computing the new bobweight, and handing it off to a shop; the crank would have weight taken off, none added, so will be a cheap re-balance.

The Air Gap might be the right intake for this because of the tight underhood space. The concern is for keeping the air cool and dense. A fresh air intake setup seems important for road courses.
 
Not a big fan of the Edelbrock cam.
 
Not a big fan of the Edelbrock cam.
Not a big fan of the Edelbrock cam.
I can lighten the pistons,( my shop). I'm considering Lunati Voodoo cam/lifters, 1,800-6,400 rpm range. Light car, lot's of gearing, 26" tire and long tube 1 5/8" primaries w. 3" collector headers. X pipe, if it will fit. I'm also considering a pair of 48mm Webber IDF's, on the 4bbl manifold. Anyone have experience, with similar set-up ? Thanks, ateam.
 
No Experience with webbers. What's the cfm equivalent? And what's lots of gear?
 
I've only used Weber 40 and 45 DCOE side drafts on 4 bangers. Beautiful tunability, and the 48's should give you more than enough breathing with the right sized chokes. Takes lot of parts to really tune them unless you can find a similar setup documented so be ready to spend some $$ on jets and emulsion tubes and chokes. Spend the $$ to buy a very good throttle linkage; sync'ing the 2 carbs can be a constant pain if you use cheap linkages. That is an advantage in the standard 4 BBL carb, but one that can be overcome.

Just IMHO on the Voodoo cam: be careful on the RPM ratings of most cam makers; they tend to be optimistic, especially on the low end of the RPM range. Lunati is no real exception here; the real torque badn will start maybe 500 RPM above the lower advertised limit. Crane is the one company whose catalog RPM range numbers tend to be fairly realistic. So if you really need 1800 RPM as the low end, then I'd look some more, but if you can use it with your gearing, 2500-6200 RPM is a pretty good usable torque band for racing. As said, a wide torque band is important in your use, especially to set the weight transfer to the rear when coming out of corners of all different gears and radii.

If you knew the road courses you would be running, and the gears and RPM's our of the corners (or the exit speeds so you could figure the gears and RPM's), then that sure would be helpful to your decision making. As I suspect you know, the 1st gear in that trans won't be of much use, but at least your steps 3-5 aren't too awful.
 
Last edited:
I've only used Weber 40 and 45 DCOE side drafts on 4 bangers. Beautiful tunability, and the 48's should give you more than enough breathing with the right sized chokes. Takes lot of parts to really tune them unless you can find a similar setup documented so be ready to spend some $$ on jets and emulsion tubes and chokes. Spend the $$ to buy a very good throttle linkage; sync'ing the 2 carbs can be a constant pain if you use cheap linkages. That is an advantage in the standard 4 BBL carb, but one that can be overcome.

Just IMHO on the Voodoo cam: be careful on the RPM ratings of most cam makers; they tend to be optimistic, especially on the low end of the RPM range. Lunati is no real exception here; the real torque badn will start maybe 500 RPM above the lower advertised limit. Crane is the one company whose catalog RPM range numbers tend to be fairly realistic. So if you really need 1800 RPM as the low end, then I'd look some more, but if you can use it with your gearing, 2500-6200 RPM is a pretty good usable torque band for racing. As said, a wide torque band is important in your use, especially to set the weight transfer to the rear when coming out of corners of all different gears and radii.

If you knew the road courses you would be running, and the gears and RPM's our of the corners (or the exit speeds so you could figure the gears and RPM's), then that sure would be helpful to your decision making. As I suspect you know, the 1st gear in that trans won't be of much use, but at least your steps 3-5 aren't too awful.
>>
48mm IDF's are rated at 340cfm, with std. chokes. I suspect supplied ones, are somewhere in the middle ? Flowed at 1.5 or 3" of water ? Lot of gear means 4:10's out back, 3.25,1.955,1.31,1.0 and .753 for 5th. I turn 67' today, and even with all of the fairly low budget compromises, this build should be plenty fast enough, for grandpa jollies. Thanks, Art.
 
Wow, that's a very lite car. I don't think you can machine the magnum intake to fit an LA head for less than just buying a new intake and selling the Performer RPM intake.
It appears the sbm and bbm , rear crank flange bolt patterns are identical. Anyone have a Pioneer part # for sbm, flywheel ring gear ? I'm making an aluminum flywheel with Fidanza steel insert. Thanks, ateam.
 
-
Back
Top