Making power out of the 318
The speedmasters are good but you need to have them gone tru by a shop and get new springs the stock ones like to break thats what my uncle said he has a 78 diplomat with a mag 360 makes 400 he is running stock heads but when he was looking into the speed masters that what he read
Hey there young fella. I’ve been real quite during this **** show of a thread going in every direction. Let me tell you a short tale.
Growing up in lower NY (Madagascar, umm, I ment to say, Long Island - that’s a joke there….) The driver my age starts at 17. You’re getting a good head start IMO.
Being your on a super tight budget, if you have the 328 now, I’d sell it, roll the money over into a 360 Magnum and build a copy cat engine. There’s no shame in this at all and it just gives a nod to the original people who did the work. Who are the people I’d copy? None other than Ma MoPar themselves.
MoPar made crate engines. A bunch of them. Your looking for 400hp? No worries. While MoPar did t rate the following engine at 400hp, all the dyno runs I have seen with this engine has slightly exceeded the mark. There is one problem to this copy cat build which I’ll address after I spell out the build.
What did MoPar do for this 360 (sized)/380hp for this crate engine? Copy cat the below build up. It’s an easy thing to do.
Any 5.9/360 engine that is in good shape will work. MoPar used the stock long block. What’s a long block? An assembled block with a full rotating assembly. Crank rods pistons bearings oil pump cam timing chain oil pump etc…. And the cylinder heads.
In other words, get a junk yard Magnum and re fit it with a passenger car oil pan and pick up.
MoPar used there own cam. It’s not Available anymore but Comp Cams has a nice slightly upgraded copy. Reuse the stock lifters. Add 1-3/4 inch tube headers if the price is right. The 1-5/8 headers will do if it has to be that way due to $$$ limitations.
Add a 750 carb and an electronic distributor. The MP chrome box ignition is very good.
The problem part is MoPar used a single plane intake which isn’t made anymore but 100% crazy expensive if you can find it. Substitute the Mopar M1 single plane intake manifold for a Edelbrock RPM intake manifold. It will help produce more low and torque. This will move the car easier. This intake has also shown to nearly flow as well as a single plane intake manifold at high RPMs.
List of parts;
750 carb
MoPar distributor and ignition box (Chrome box)
Edelbrock RPM
Comp cams copy cat cam for the crate engine.
Valve springs for the cam
Car oil pan and oil pump pick up.
Headers into a 2-1/2 exhaust - mufflers of your choice.
(For a “On the Cheap” exhaust, Summit racing has a complete set up that is very good.)
If you go to a junk yard for the engine, make sure you get the flex plate at the rear on the crank! Very important.
MoPar used the stock production line 5.9/360 engine that uses stock parts except this listed above for the crate engine program on this engine as well as the 360/300 hp engine.
Call a converter company up with all the specs of the engine as well as the cars rear end gearing, tire size and what transmission you are using and pay the piper for a good converter. This is an expensive part but sooooooo worth it, so save your money!
For a gear ratio, I suggest a minimum of 3.91, 4.30 & the max.
When these engines appeared at the drag strip, in gutted Dusters, fellas would run low 12’s easy. A few I have seen ran into the 11’s. Yes! Very light car and dedicated to the drag strip.
That’s what I’d do.
Keep saving up the money!
Best of luck with your pursuits!