The RSR was a purpose built engine with many parts not common to production engines of the time. In fact some RSR parts were used only on the RSR.
The crank was one.
The case was another. Aluminum that looked more like a 2.0 aluminum than a 2.7 mag. The stud spacing was larger than 2.7 yet smaller than a 3.0 . In fact that meant that the cylinders and heads would only fit the RSR case.
Many even had aluminum chain sprockets.

NHRA 6000 horse power engines are all a version of MFI.
There are no top flight teams running EFI making anything like 6000 horse power. Why?

Hey, I thought you said no pissing contest. Sorry, I know absolutely nothing about NHRA engines. Not exactly apples to apples, though - don't those engines consume serveral liters of fuel a secon? I do have faith in the almighty computer though...

Either way, MFI is a great system from the older days...

-Wayne

Up to 16 gallons in 4 seconds with no computer.
$1200 per 55 gal drum.
They pump so much fuel that if a spark plug misfires the cylinder hydro-locks and blows the head right off.
In other words, if the fuel isn't burning when the piston reaches the top, there is not enough squish area for mixture and the piston dome so irresistible force meets immovable object and bang.

Wayne, I will have to give you the throttle response on these monsters is immediate but not too good on the street.:)

Henry

If one takes Bruce Anderson's book as being accurate on this score, the 2.8 RSR had the mag case with the '65-77 911 case head stud spacing.

The early 3.0 RSR had the aluminum case with the head studs spaced between the earlier case spacing and the 930 case spacing we all know and love, and had special heads to match of course, along with its other trick stuff.

All he mentions about the 2.8 RSR crank is the fillet radius change.

Since I have never owned or worked on either a genuine 2.8 or 3.0 RSR factory race motor, and looking at one isn't the same as working on one, I have no personal knowledge of what is or is not in them. Fancy, expensive, hard to find race parts, of course.

I did see in Bruce's chart (good to hear he is recovering well from his heart surgery) that there were some late '79s or early '80s race motors which had 66mm cranks, so I suppose those are the 66mm 9 bolt cranks. If a guy got ahold of a good one of those, he could use that with a '78 -89 930 case to build a short stroke 2.8, though I suppose it would be safer to use the '76-7 case because ordinary 66mm cranks are surely easier to find and cases are less apt to get damaged than cranks.

Walt Fricke

Walt, that's what I have read as well. A friend of mine that was a driver from that era stated that early on Mag was used. But later, teams were switching over to early sand cast cases for longevity/reliability.

I stand corrected on the fact that the early 2.8 RSR case might have been made of mag. I stand firm in my beleif that no front running pro team ran a 2.0 case to make a 2.8 RSR engine.

LOL I may be suffering from CRS maybe the factory started to supply aluminum cases for this. Its been a while since I heard the story.

The 2.8 cases were definitely mag, we have a few at the shop right now.. As we have a 73 RSR(real one) that we just built a motor for.. and a Real RS 3.0... very cool car..

I see you are in Minneapolis you should stop by, we are in Bloomington MN... or just check the website Flat6.com


Steve
Flatsix inc.