I have a few questions about building a 400/512. First, are Edelbrock Performer RPM heads a good/big enough head for a 512? Second, will 1 3/4" tube headers hooked to 2 1/2" diameter exhaust system be large enough for a 512? And third, is there anyone else other than 440 Source and Muscle Motors that sells 400/512 rotating assemblies?

That head works, but it works better after someone does a CNC port on them. ...or just buy Trickflows that are already ported.

If it is a street car that exhaust will work fine.

I didn't buy a kit but rather bought a Molnar crank, Molnar rods and Mahle pistons. It was great quality parts for very similar cost of a "kit". There is a handy chart AndyF posted in the tech section that helps with rod length and piston selection.


http://www.moparts.org/Tech/Archive/bb/BBM_Stroker_Pistons.html

RPM heads work just fine on a 512 for a street car. They are way too small for an all out race engine but they will work okay for a 10 sec type of bracket car. So the answer is the usual "it depends".

What are you starting with, and what do you want the final engine combination to do?

A standard port head will have peak torque at a lower RPM than a Max Wedge sized port head, so it partly depends on where you want the torque curve to be and total amount of power. If your just building a street engine than the standard port heads are fine. For a race engine, you would want the larger port size heads, but being a low deck really limits intake choices when using Max Wedge port size heads. I think only Indy sells cast intakes for the max wedge low deck combination?

Standard port heads allow a wider selection of intake manifolds. For the street, the RPM Air-Gap is popular.

I have the TTI 1-7/8" headers on the mild 505" 440 with Stealth heads in the convertible with the TTI 2-1/2" "X" crossover exhaust. In that vehicle I wanted good header clearance and quiet sound. If your building a race or street/strip setup like the 500" 400 MW victor head engine in my Charger, then there is some performance to be gained with 2" headers and 3" exhaust.

I am tying to save up to build a 512 (really 505" 440) for my Jensen Interceptor using the Trick flow heads, but medical issues are killing my bank account. This setup I plan to build my own headers with 1-7/8" first step, and either build step headers or Tri-Y headers for the car.
Either way, the tube diameters will grow larger from the initial 1-7/8".

My home ported RPM's push my Dart into the mid 9's low 6's but at your cubes, I'd buy a better head that has the flow potential for 512 cubes other wise what's the point. And the exhaust, no way I'd put less than a 2" header and 3" pipe either may as well build a Small-block......... And no 4150's either.............

More cylinder head and bigger headers would be much better obviously. I am in the same boat though. I already had heads etc but needed to build a new short block. Well since it costs the same to build 512 with new parts might as well go that route and leave room for more cylinder head later.
I didn't use a kit. I bought a 440source crank, 6.7 rods and a shorter 1.12 piston that's generally for the 4.15. But with the longer 6.7 rod it comes out .010 farther in the hole which can be decked. But the pistons are lighter and the rod ratio is better.

I am like GY3 and went with the Molnar rotating assy and Icon pistons and topped it off with the Trick Flow 240 heads and their Intake, I am about a weekend away from testing her out.

For your deal I would buy the two inch headers with 3 or 3.5 inch collectors and put a 3 inch exhaust system on the car to start with now instead of later
You've already made the motor bigger for more power, correct
Do the same on the exhaust now instead of later, it always costs more later
My old 440 powered Dart picked up .8 ET and 8.+ MPH in the 1/4 mile by removing the two and half inch exhaust system from the car
It had the old Thrust 2.5 inch Turbo muffs hooked up to the Hooker 1 7/8 Hooker fender well headers with 3.5 inch collectors back about 18 inches with 2.5 inch pipes to the Turbo mufffs and then around 18 inches more of 2.5 inch pipes out to the side exhaust Very restrictive

If it's a real street car, I would stay with 2.5" mandrel bent pipes. Yeah, you would be giving up horsepower and not an insignificant sum of it. With a 3" exhaust, however, you are going to have to really consider packaging constraints and noise. A 3" exhaust, all things being equal, will be significantly louder.

My '65 Fury has 1 7/8's tti headers, a full 2.5" tti exhaust out the back and the longest body of muffler that Borla makes. When I ran that exhaust on a mild 383 it was nice and mellow. After I moved to my 512 the car is now noticeably louder, with an emphasis on low frequencies. If I had 3" pipes right now I would definitely be looking for ways to quell the decibels. Additionally, there is no way in hell I'd run a larger header on my car. The current pipes are big enough for an afternoon of head scratching and vocabulary building as it is.

And for reference I use a 512 with a Molnar crank and rods, Diamond pistons (stock PN), and Trick Flow heads. It makes around 10.3:1 and uses a Straub solid roller cam.

Yes, it is a street car. The reason I asked my initial questions was because I already have the parts I asked about and would like to use them. I was originally going to go with a 470 but people keep insisting I should go 512 so I just wanted to see if it was feasible with the parts I have.

For a street car the heads will be fine. My 4000lb wagon has been 11.0's with a small mech cam from Comp. The heads are untouched RPM's except for making sure the valves seat properly and the guides were not too tight. I shift at 5500 and cross the stripe at 6100(my convertor is a little looser than planned).
I would go w/a 2" header. I run TTI stepped 2-2 1/8". I will be adding a little more cam and head work later so I will grow into them. I will say if the Trick Flows had been available when I built this I would have gone that direction.

Ohio Crank, scat, Molnar are other sources. I do have a 440 source kit. It was spot on per my machinist.