[tomk_22]

how do i set the rotary timing on a 91 formula plus 521cc oversized .020? i know a little about how to set it but not sure which timing mark to use on the MAG side and what the correct angle is or do i just use the arrow on the case? what shoud this sled have for jets it has 330 & 340 now

 

[finn]

Sorry I do not have the timming numbers at home.....have them at the shop....any way there are two numbers ...as an example 142 / 68 what this means is with the Mag piston at top dead centre using a protractor or rotary valve timing disc measuring from the bottom of the mag side intake port mark 142 Deg. counter clockwise . them from the top of the same port ( mag.) measure 68 Deg . clockwise.. so now you have two lines one somewhere about 11:00 and the other about 4:00 with the crank still at mag. TDC. install the valve within these marks. you may have to flip the valve over to get the best match.. if you can't get the numbers...I will post them later if you need .....Jari