Well back in the day I had '76 Scarab along with a good friend of mine. They both came stock with sbc and were called 280TRS. Stock came with 21" cleavers and my friends Scarab had a little work on it but still used the 21" and cupped them a little bit. Of course there were no Hydromotives or Mirage props back then. Since then I had a 9m Mirage SS and tried a half dozen props on it looking for best midrange and top speed and the mirage 3 blade props worked the best. The cleavers slipped a lot midrange but top speed was not too far off.

Thanks for that, mines got the sbc in it, top speed with no trim control was 43mph

Well something is wacked. The boat should run around 57/58 mph with clean hull, straight props, tuned up and trimmed out. If I remember right it was turning around 5200rpm. You'll get there, good luck and enjoy.

Ya, I didn't have my trim pumps wired in, so that was full drag in the water, I'll get it all dialed in this weekend

I would think a 21 mirage plus would be close

21p mirage will be the best prop for your boat with those motors. 23p will be the easiest to find used and will work but the rpms will be a little on the low side for optimum. More important is to get your trim working. you are pushing too much water for any props to make a worthwhile difference.

Agreed, pumps and cylinders are being rebuilt now and will go on, then hopefully I'll have a better idea on what it's doing/needing

As others stated a 21 Mirage would be the best choice for that hull. When I was looking for a Panther I looked at a beautiful 1976 300 with the 260 or 280 package. It ran out at 55mph with 21 cleavers. My TRS Panther is the same hull as yours and I've tried every style of prop out there. A 27 Mirage is the best prop I found. Stick with a plane Mirage.

I've got a pair of 21p mirage props I bought for my 78 Scarab 300 with BBC's but they're too low for me to use so I need to sell them. I only got 55mph out of the boat with them and had plenty of throttle left, but with small blocks I bet they would be perfect

I've got a set of mirage 21p labbed on there now and best i was getting was 53, I'm gonna try a set of 25's and see what they'll do after the performance parts go on.