964 cams are a recommended upgrade for CIS motors. If you don't have it, buy Wayne Dempsey's book on Rebuilding 911 Engines...he has numerous tried, tested and true upgrade options for all motors.

Regarding twin plugs, given your budget conciousness, this may not be the best route as twin plug distributors run $1500-$2500. That said, twin plugs allow 10.5:1 CR on premium pump gas. 964 cams (and any cam designed for a motor w/ common plenum intake) have minimal overlap, so your dynamic compression will be higher than performance motors. I would verify if you go with twin plugs if 10.5 CR is optimal. It may actually be lower, in the 10 to 10.3 range.

Hopefully Henry or Steve will chime in to confirm.

kenikh
Thanks for the advise I have the book on order I am just a bit impatient. Only reason the budget is restrictive right now is because I am not working, once I pick up a decent contract the budget will increase and therefore I may go the carb route eventually......

Maybe this will help; it's what I did:

Pelican parts for gasket sets, misl pieces, JE pistons and rings, bearings $2,000 +/-
Used 46 mm Webers from this site $2,500
Used GE60 cams from this site $500
Machine work and head re-build (includes twin plug) $2,500
Twin plug dizzy and wires $2,300
Misl. Crap $1,000

My budget was $7,500 and I could have gotten there without twin plug. A 9.5:1 motor using re-plated cylinders, GE60 cams and 46 Webers will rip. You could build this for around $6,500.

Not sure what your budget is but good luck!

Lindy

One suggestion - skip the 46mm Webers - they are a PIA to tune. PMOs are the way to go. This is one of the pennywise/pound foolish situations.

Mine work great. Nuff said.

Lindy

Last time I checked PMO 46's were about $3,600. The Webers I got (maybe I got lucky) are in great shape and I used the $1,100 difference to fund other things. Plus when I looked into PMO's, there was at least a three month wait to get them. You're right, PMO's are better in some ways and maybe a little easier to tune but I think that's like saying a 24" bike is easier to ride than a 26" bike.

What were the problems you found with your 46mm Webers? I'm guessing you have had a few sets.

Lindy

True. The big difference is the problem with the progressive ports by the butterfly for proper transitional mixture. The PMOs are much better.

BTW, you got a freakish deal on your 46mm Webers. I haven't seen any sets for double that...

Quick update. Now almost end of August and been very busy. Have been back working again for 3 months and that is getting in the way, due home 2nd September then the fun begins.
I have all the parts assembled for the re-build. The heads are at the shop now being re-built.
Oil cooler has been internally and externally cleaned and pressure tested.
The conn rods have been cleaned, balanced on the crank and new wrist pin bushings installed.
Cam towers cleaned.
Case cleaned and repairs made.
All engine tin, upper and lower valve covers, chain cases and covers, fan, strap and housing cleaned and powder coated.
List of new parts as below
http://forums.pelicanparts.com/uploa...1282306020.jpg
Not too bad cost wise I dont think and many thanks mainly to jpkelly3, tom1394racing and a few others you know who you are....