I��ve got a 351C in my 1979 Fairmont Futura which is currently built toward the ��street�� side of street/strip, but I��m hoping to take it to the strip on occasion next year. The engine is built more toward torque than rpm. Toward that end I��ve installed a set of Australian 302C small port, small chamber heads. For what it��s worth, I��m running a Comp Magnum 280 hydraulic, MSD ignition, bolt-down FRPP roller rockers, Weiand X-celerator intake, 750 (3310) Holley, 1-3/4�� swap headers, C6 with 10�� (advertised 3K) converter, and 3.70 gears. The car, with me in it, should weight around 3200. Front/rear weight percentages are 56/44. Following are my questions��

1) I, like many others who have posted, am considering building a stroker at some point in the future, so am trying to do some research. I��m leaning toward the Scat 3.85 stroke crank. If I go with this piece, would 6.03�� Aussie connecting rods (with polished/peened beams and ARP bolts) and custom pistons make for a reliable bottom end if I were to keep the engine under, say, 6K? The rods would make for a decent (not great) rod/stroke ratio 1.56+ and would be less expensive than aftermarket rods; the short compression height pistons for this setup would decrease weight, and I believe my reworked heads would support the cubes. While I��m in the viscinity of connecting rods, it appears that Scat offers both 2.311 and 2.1 journal sizes for this crank. I know if stock cranks are stroked for use with SBC rods that the rods have to be narrowed. Can anyone tell me whether Scat cranks with the 2.1 journal are designed to accept stock width SBC rods. It would make sense that they are, but I don��t know. Also, are the 2.75�� main cranks actually designed to be a true ��drop-in�� in a production 351C block or are they designed for the 351W and/or SVO block crowd and need additional components like a spacer ring at the snout for the damper, special main thrust bearing, etc.? Just trying to avoid surprises.

2) What kind of rpm and/or spring pressure will the bolt-down type roller rockers support? I know with the 5/16�� pedestal bolt that there are obviously limitations as to what they can endure, but don��t recall seeing any specs. When my goals were mostly aimed toward street use, this wasn��t a particular issue in my mind, but now that I��m more seriously contemplating running it at the strip, reliability becomes more of an issue to me.

3) Since I��m not envisioning either my stock stroke C that��s in the car currently, or any subsequent engine seeing lots of revs, I��m thinking very seriously of putting a hydraulic roller in at some point in time. I don��t believe that their extra weight should be a major factor in regard to valve float since my revs won��t be that high. More to the point, my question is this: Given my plans for the HR cam, what should I do to address the C oiling system? I��ve got the supplemental oil line that runs from the port up by the fuel pump to the rear sending port. Is something like the Moroso restricter kit good or bad? As I��m sure everybody is aware there are all sorts of opinions out there about what to do or not do to address the oiling issue.

4) For those of you who race, given the bit of information I provided about my car at the beginning, does anybody want to offer any guesses about what kind of ET I should be able to pull out of this combination? I will probably run at tracks that are around 600-800 ft sea level. Also, I have raced in the past, but not for years, so I��m not a rank amateur. I realize the 3.70s aren��t conducive to the ultimate times, but they��re at least a start. I��ve got a set of ET Streets, 28x11.5, that will be what I start with.

Thanks for any thoughts or opinions anyone cares to share.
Scott

The Weiand Accelerator for the 2V heads has extremely large ports outlets. They are quite a bit larger than the intake port openings on your heads. There is a severe mismatch there.

I recently finished porting two sets of Aussie heads, along with an Offy Port-o-Sonic and a Weiand Accelerator. Both are single plane intakes for the 351C.

I like the Weiand for an intake that will be used with heads that have the intake ports opened up, but it's just too large for stock heads. The Offy would be a better choice here. BOTH need considerable plenum work.

Porting the intakes...

Before starting, I cut port extentions to weld into the plenums at the four corners to help lengthen the center runners. A local machine shop installed them for me... then it was time to grind.

I bolted one inch spacers to both intakes and began hogging out the plenum, blending the sides down into ports with a 90 degree die grinder. The end ports were blended the most. They were hogged all the way to the top of the intake... to where the spacer bolts on, and blended smoothly a couple or inches or so into the port. The Offy was welded on the outside to allow maximum blending of the plenum. This was unnecessary on the Weiand.

The runners of the Weiand are huge all the way through, and were untouched. (Yes, it IS the 2V version #7516 I believe) The Offy needed its runners ground out, but I was unable to reach all the way into the center of the outboard runners. The Weiand turned out the best. It's quite purty.

I have no flowbench, but the heads seemed to benifit from some serious unshrouding of the combustion chamber. The exhaust valve is totally surrounded by chamber wall, and got a LOT of work. The intake port was unshrouded as well, and seemed to benefit from widening the floor of the port shortly before the turn into the combustion chamber. The port just looked "funny" before that was done.

There is a LOT of grinding to be done to a set of these heads. I would like to know someone who could test them on a flowbench, and if I find someone, I'll post the numbers.

These were a pain in the a$$ to port... a LOT different than the 289-302 heads I'm used to grinding on. Anyone else grind on a set of these? What did you think about them?

Later, and Good Luck!

First thing that grabbed my attention was the c6. A c4 is lighter, shifts better and is around 3-4 tenths faster than a c6.

Second thing was the possibility of a stroker with those small 2v heads. A big inch motor likes a lot of airflow and those heads arent capable of it without a ton of work.

The oil line is a good thing. I second the advice for a solid cam and oil restrictors to the top end. You'll also want a larger oil pan.

For good reliability, the heads will need machined for real screw-in studs and guideplates. I wouldn't trust that conversion kit for serious duty.

The hydraulic roller is limited to around 6000 rpm. A good solid works similarly with moderate durations. It's also less expensive. Ask around for advice on which ones to use.

A 750 vacuum sounds a bit small, but will be alright with the initial combo of a 3.7 rear gear and MT ET-Streets.

Grinding on the heads and intake will help... as long as it's done right.

I don't know much about the cranks....

Good Luck!

n2oMike: Thanks for your comments about the Aussie head prep and intake porting. Because I knew my post was going to be long I didn��t elaborate on what's already been done to them. Because I didn��t trust myself to do this, I sent them to a shop to have them reworked. This included getting both sides of them ported and polished. The intake port actually matches up to the X-celerator intake, so the mismatch you warned me about doesn��t exist, but I do appreciate your heads-up. The chambers were also opened up to unshroud the valves and polished. I also had oversized valves installed 2.07?/1.71. Chamber volumes run in the 62-63 cc range. I��m sort of kicking myself now for not getting them converted to adjustable rockers when I had the chance, but oh well. I also kind of wish I��d gone ahead and gotten them flowed after getting the other work done, but as I mentioned in my first post, I was really building them for street use, so didn��t see the need (other than out of curiosity). The shop that did the work said they��ve done other Aussie heads pretty similar to these and they flowed around 240 and 170 @ 28��. I��ve seen other figures that showed higher rates than that, but they theoretically ought to be somewhere in that general range. Also, since this is in a fox chassis, I��ve got the double sump pan. It holds seven quarts with a rear sump pickup and some baffling.

kid: I was thinking I��d read in one of the many strings I read through over the past few days that you��d said something that made me wonder if you weren��t from the Iowa. I��m glad you��re as close as you are. That��s an easy drive to track you down if you��d ever be of the mind to get together.  How much does a C4 weight in comparison to a C6? It seems like it would sort of a win-win to have less weight to pack around and less power loss�� Now that you know a bit more about my heads, do you think they��d come closer to working on my hypothetical stroker? I guess for the time being I��ll continue to ponder my camshaft choice. I��m guessing that the car will still see considerably more street time than track time.

quote:

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Originally posted by futurattraction:
�� Now that you know a bit more about my heads, do you think they��d come closer to working on my hypothetical stroker

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My opinion,

No.