I run 9901 and 029 with those, I think 021 is same length as 029 but 021 is wider curve, so should do same job.
I just like 9901. With that I run 0.9 springs.

We want to thank everyone for their support in 2013.

Merry Christmas and a Happy New Year!

Does anyone know if the newer style heads fit the old plus 4's. I have the older version and love how it runs but hate the huge head and would like to change it out for the newer smaller one. Thanks for any advice.

No, doesn't fit. (Crankcase square top, newer have machined round top so low cg head can drop down over it)

I was thinking of making one out of brass. I will keep that in mind the next time someone has a broken screw. Thanks.

Any new experience out there with the Roma? I've seen a few people complain about bearing problems for ex.(and possibly rods?), which would make me a bit wary, for an engine in that price class..

The Roma is a very good engine. I raced one for a few months without any bearing or rod issues at all. The engine had a very smooth power band with a strong top end. The mileage was average, I was around 9 mins give or take. For a truggy I would put this in between a p5 and the keep off 21-7. 9901 pipe with either 021 header or 001 (more punch).

The Roma is very reliable and can handle high RPMs better than any other large (.22+) engine. It's popular with the GT racers and they spin them to high RPMs (35k-40k) without a problem.

Any word on the new motors?

what is the rear bearing size for the keep off +4?

I have a P5 with 6 head screws anyone know anything about it ? thx

In the keep off line, Nova uses a new rear bearing that as far as I know, only Nova produces. It is part# nov16802.

OD is 26 I think? as compared to the others which are 25.8.

Yes... it's old.

Relatively short run of engines.

Somewhere between 1999-2003 range I think. Little fuzzy about that.

Post pics for nostalgia

SEF is correct , get a hold of www.serpentamerica.com for the bearing