Budget Stroker

[Leon]

The E31 was in '71 240Zs as well, up to a certain point (6/71 maybe?).

[chuckles]

This is s 4/71 build, so maybe it's OEM.

[ctc]

I quote from the this thread Custom Cylinder Head Building post #9 (the right honorable BRAPP)

 

The MN-47 is a round port head. The round exhaust ports, (with the liners still intact), are excellent for mild race and hot street engines. Also of note, All the round port heads, (N-47, MN-47, and P-79), have a smaller intake port. At approx 1/2 “ into the port, the port takes on a “D†shape, this helps bias the port centerline which in turn helps to aim the incoming air flow toward the center of the cylinder. This is great, but for maximum effort high RPM breathing, that smaller port is a hindrance to overall flow. These “D†shaped intake ports compliment the round exhaust ports nicely for mild to hot street, and mild race applications. Especially for a street engine that is asked to have some civility at part throttle conditions like having to drive through town back and forth to work and in stop and go traffic on your way to your favorite bonsai back road. These "D" shaped intake ports and round exhaust ports found on the N-47, P-79, and MN-47, in my opinion, offers the best performance with the least compromise in around town drivability and low end and mid range torque.

The square exhaust ports of the N-42, E-88, and P-90, allow for considerable exhaust port alteration allowing the engine to breathe freer at the higher RPMS, though low rpm performance will suffer as a result. The Intake ports of these same heads are also larger than the intake ports in the N-47, MN-47 and P-79, so less carving.

 

In short, the N-42 offers more “all out†potential, but at the cost of low rpm and part throttle drivability. This same radical head on a street engine that is to be driven around town would be a poor choice. This N-42 works best at WOT and above 4000 RPM, where as the round port heads do their best, (depending on how they are set up and built), from as low as 1500 RPM up to 6500 and will have decent manners around town.

 

 

Me thinks thou does searcheth too little......

 

The cheapest option is to build what you have. The N-47 will be fine. A P79 core, should be easy to come by. Search on emissions here as well and you will be suprised how worth your time that head can really be.

 

If you truely want the least cost into this motor and the most benefit. Spend time, not money, on research.

 

A lot of people have already given you some very good options.

 

Chris

[chuckles]

Hey guys, been a bit since was here. I'm starting in on the 2.4/2.8 engine work in about a week, so I'll let you guys know what I find on the 2.4, and if it's complete toast.

[dylanh]

im over in lake charles, glad to see a build going on close to home. Hoping to get in an s30 myself if i can get my 240sx sold. good luck

[chuckles]

im over in lake charles, glad to see a build going on close to home. Hoping to get in an s30 myself if i can get my 240sx sold. good luck

 

 

Thanks, I need as much luck as possible!!

[chuckles]

update. 240 engine was trashed. The bores were completely rusted and would take 120 or so to clean them up.

 

So I got a great deal from Dave Rebello on a 3.0 stroker setup. I send him the N42 block, E31 head, and 240 rods. He works his magic and sends back. Then I will assemble the engine and away we go. Estimates are around 250 to 275 hp with SU's. Chekcing on Bore Bore pricing for SU's today.