Stage-1 Block w/out Power-6 Logos

[James Racing]

I have a 4.1L Stage-1 off-center block that has "SP"
where the Power 6 logos are on other blocks I have
seen. Anyone know if it's an earlier or later casting
than the Power-6 embossed blocks? BTW- The block
number ends with 016. TIA.

 

[flynbrian]

I have 1 Too!

Hi,
I have one of these blocks too, I picked it up from a Well Known Engine Builders shop, it is a 4.1 has SP cast into the side, with a Raised Star cast into the side, above SP, had no clue what Iwas looking at other than I knew it was a 4.1 and it looked beefier in the casting and the casting is really dark, like a Stage 2 block. I went ahead and bought it, also got a new 4.1 Stage 2 block from the same place, so I figured it might be a better casting, cause where it came from built busch motors, IMSA motors and Indy Motors, hopefully someone has info on them.
Good Question!!! Thanks,
Brian...

 

[EightSecV6]

From what I was told, the SP means "Special production" I had an off center stage 2 that was labled the same way, I believe it is an early model, mine didnt appear to be different structurally or cosmetically compared to the later model stage block.
Bill Anderson

 

[flynbrian]

Cool!!!

Thanks Bill!!!
What is the Horsepower limit on a Stage 1 block???

 

[EightSecV6]

I wouldnt be afraid to run 750 or so with billet caps.

 

[flynbrian]

Outstanding!!!

Bill would you add a Block Girdle too? I was going to build a Second Stage 2 Engine, eventually for my StreetCar, but I think I'll just go with the Stage 1 block, I see why the Stage 1 blocks are so coveted.
Bill the 750hp you spoke of, thats with good rods and a steel crank?
Thanks for all the info Bill!!!