I used to use that formula, with pretty much the same result.

Then I found out the motor made more power with a 780.

No they're not.

But, assuming it's a worry to you, run a 5.315 rod in the 347 and then it's exactly the same piston.

I actually prefer the 5.315 rod 347 combination. The extra rod length is near to meaningless. And I have several 331s running out there that do just fine as well.

I actually do not like the oil rings perforating the pin bore. What is considered an acceptable degree of oil control in a hot rod would be considered totally unacceptable in any OEM application. Most performance guys will never know since they change the oil every time the wind changes direction. Add to that the fact that the ring groove spacers are nowhere near as well made as the rings nor the pistons - it's an uncontrolled and un-necesary variable - you can often readily feel the difference in ring drag when turning the engine over on the stand.

The oft quoted carb formula is inherently flawed. Back when carb companies used SAE standards instead of making up cool sounding number, the carbs were rated at 1.5" of vacuum drop below the plates. You NEED some sort of reference restriction in order to derive a rating - but the values arrived at reflect a restriction in airflow into the engine - exactly the opposite of what you want.

I do not know how much power you are looking for but a nice 331C.I. with the KC 165 heads, hydraulic roler around 224/232 and a Performaer RPM intake should make a easy 425 to 435HP and I would think about the same torque.
If you have to run the header that you are talking about anything bigger or with a better head would be limited anyway. The exhaust on these cars kills more power than most people know. I have people buy big heads and then stick small tube headers on them covering part of the exhaust opening and the pipe size will not the exhaust flow as it should. The header pipe size and bolt pattern need to be considered when getting headers. This will in turn have a lot to do with the engine size and other things. It all has to work together.
I think you will be surprised at how well the engine will work for you.

Good luck, Keith Craft

Thanks Barry and Keith for your input.

The headers will be JBA shortys with 1-5/8 primaries and 2-1/2 collector, this shoud not be too restrictive and will clear my footboxes.

Uwe

Uwe let me know when we can send some more parts to Germany. Good luck with your project. I think the headers will work pretty well with that project.

Thanks, Keith

Did some small adjustments for the cam and came out with the following character for the 331.
The numbers are not real, I know this, but I use programs like this one just to see if the character of my planned built will fit my needs and the defined parts will correspond.

I kept the 112 lobe separation but adjusted a bit the duration to 266/274 or 216/224 @.050.

The curves will more or less look like this in theory ...

Simulations are nice, but don't rely too heavily on them. Horsepower and torque curves/peaks depend a lot on cylinder head flow as well, and until you get the heads in house and flowed (never go by advertised flow numbers), you really can't say with certainty where the numbers will fall.

That looks like the specs for a Comp Cams XE266HR. It will be a fairly mild camshaft in a 331.

Back in town with news. All the bits and pieces are collected, here and screwed to the bare metal. The 331 and 347 shortblocks from Keith arrived and fulfilled all my expectations.

My one was ordered with a matching flywheel and damper.

For the thermostat housing I have choosen a Performance Stainless Steel one, the heater hose fittings from the same company will arrive in the next few days.
I used adjustable guide plates from CompCams instead of the supplied AFR parts delivered with the heads as well as CompCams hardened pushrods.

The thrust plate is the one from Precission Oil Pumps with the needle bearing, the oil pump and drive shaft are from the same company.

All fasteners are from ARP, the main studs are the ones for the windage tray to use them for mounting the pickup tube.

The rear sump canton oil pan is baffled, has trap doors and integrated scraper and clears the stroker kit.

The Cobra open letter valve covers are a must for me so I had to install milled down valve cover spacers to clear the scorpion rollers.

The complete thing is topped by a Weiand stealth and a MSD Atomic with a Cobra round air cleaner from Tony Branda.

Now the engine is waiting for the painted MK IV chassis and body, to be delivered by Wednesday next week latest.

Some pics for the gear heads:

Some other detail pics from the assembly process: Checking crankshaft end play ( which was fine, sorry Keith, the nitpicker is back)and cam end play. The new timing cover was completely deburred in the water passages because the tool parting lines where massive and I just don't like it this way.

I checked nearly everything but not the supplied AFR rocker studs and I payed for this.
Two of them had the threat not worked out completely, the pitch looked like not rolled correctly and more like a trapezoid thread what I found out the hard way.....
As I applied the AFR recommended torque to the rocker studs the thread in the heads gave up immediately and I had to remove the left head to fix the damaged threads with TimeSerts.
Have the more actual AFR heads inserts in the threaded holes for the rocker studs?

Timing indicator is mounted and finally adjusted to measured and approved TDC.

Nice small detail, my name "UWE" on the counterweight :p, the second short block was ordered for "WILLI"...no, not the one to be freed..

These are the only wires to be used with the Atomic EFI.

The next update will be done after the thing is back to life.


BTW, I have a rare pair of 351 Cleveland Valve Covers available with "SHELBY" and the "SC" script on top. It is mid 70s original Shelby aftermarket stuff for the Panteras or Cleveland powered Mustangs.

UWE, that looks like it's going to be a very nicely matched combo. If you don't mind I'd like to hear your thoughts on the Atomic once you get it running. I'm in the process of changing my 462" FE over to the Professional Products TBI which seems very similar.

Will share my experiences with the MSD but not before middle or end of July, sure.

Some update about the car and engine. The complete assembly is ongoing.

http://i74.photobucket.com/albums/i2...6/P6062519.jpg

http://i74.photobucket.com/albums/i2...6/P6062523.jpg

http://i74.photobucket.com/albums/i2...6/P6062524.jpg

http://i74.photobucket.com/albums/i2...6/P6062521.jpg

Absolutely beautiful!

Regards.

Back with some late update. The 331 has seen 700 km till today and runs great. The MSD Atomic is the easiest system I have installed ever.

It was so easy to istall and set up. Great!

The complete thing looks like this now:

http://i74.photobucket.com/albums/i2...6/P9022626.jpg

http://i74.photobucket.com/albums/i2...6/P9012618.jpg

http://i74.photobucket.com/albums/i2...6/PA212668.jpg

http://i74.photobucket.com/albums/i2...6/PA212661.jpg

http://i74.photobucket.com/albums/i2...6/PA212672.jpg

http://i74.photobucket.com/albums/i2...6/PA212664.jpg

Quite keen on the hood scoop....mine is "short" and I cannot run a decent air cleaner.

Do you have any dyno numbers on the 331???

How do you like the 165's? I would like to rebuild my box stock 5.0 with a set of AFR165C's, the factory "competition" model. Might put a stroker in it, if the block will stand it I would go with a 347 stroker, though...might use that longer rod/piston combo recommended by someone a page ago...at any rate, your ride is one primo A/C and you should be incredibly proud!

Cheers from the U.S.!

Dugly :cool:

Thanks,

The 165 KC ported AFRs were ordered and delivered before the decission for the 331 was made.

They were planed for a stock 30w rebuild. For a future 302 based stroker package I would go directly for the bigger heads.

Dyno results, If my job allows it, can be available middle or end of next year.

I have some plans to optimize the exhaust system behind the JBA headers.

In the MK IV the air cleaner lid sits more or less 1/4 " below the hood and the scoop could be eliminated, the scoop is not necessary for clearence if you go with a intake not higher then the Weiand Stealth and my Carb/EFI-aircleaner combo

With the FE or Cleveland in my former car I needed the scoop for use of the small round aircleaner in the turkey pan or the big oval one.

Uwe

UWE, thanks for the feedback on the Atomic and your MKIV is drop dead gorgeous!