measuring exhaust port height on a looper

[OMCFREAK]

I'm in the process of raising the exhaust ports on my 2000 3 liter looper up to 1.65. I'm not sure if I should measure the port to the deck where the rolled edge into the liner starts, which is about 1.65 right now, or from where the entry into the blocks exhaust port starts, which is about 1.70 right now. Don't want to grind any more before I know.

[racer]

Problem with measuring to deck height is the block has a +/- of .012 deck height spec. Depending on your rpm goal and what is done to the intake side 1.65 on a zero block is IMO already high for most applications. If you can find a 88-92 block or a 225HO copying the exhaust port on them will give you more than enough port to run 7000RPM. If you want to run them at that or more rpm you need to make sure all the rest of your parts are up to it.

Measurement should be to the square part of the deck surface (again Zero deck). When I did them I did ports with a degree wheel, first using the top of the chamfer and second to the port opening.

[OMCFREAK]

Thanks for taking the time to reply to my thread. I ended up only taking the ports to 1.70 after thinking about your reply. I haven't done anything to the block on the intake side. I use an Evolution Marine billet intake system with velocity stacks and big bore carbs. Jetting is 76 on the top 4 and 78 on the bottom 2. Idle bleeds are 20 and mid bleeds are plugged. Main bleeds are 104 on the top 4 and something smaller I cant remember on the bottom 2. Timing was at 15 last time I checked. Don't plant on turning the engine past the limiter in the powerpack. Compression before I did anything to the ports was 160ish. I do have an open deck 89 engine that I'm also going to build later, adding fingerports etc....

[racer]

If its apart I would at least clean up the glue lines and match the block to the sleeve being careful to not change any angles.

[OMCFREAK]

Thanks. I did hit the glue lines real quick and there was very little to do to in the way of block protrusion into the sleeve ports, but I did knock a little b ack here and there to match the sleeve.