i spoke to the guy who runs the nearest repco, who has just rebuilt his ford using crow bits. he rang crow for me after speaking with them, and I got this response:

the XR ones they stock are the beehive type (kinda smaller at one end)

they need new retainers (supplied in kit). they have 90pounds compression force, and 240 pounds at 1/2 inch lift.

they are $230 dollars for the AU.

The Double springs are the normal type, and get new retainers in the kit.
they have 115 pounds CF, and 275 pounds at 1/2 inch lift.

they are $150


Both Repco, and CROW recomend if i were to use new valve springs that I use the doubles. They both agree that the power loss is not even worth thinking about, and that you would find better bottom end due to the more precise valve action, albiet again, you wouldnt really notice it.

also the boss at repco who i spoke to said he took his springs out after 3000ks to have a look see and they had lost 25 pounds of compression once run in.

save your money and keep the doubles, not worth the hassles and extra coin to swap over.

Im going to ring wade tomorow and see if i can speak to the tech guy keith, and see if he reckons i should even worry about new springs. thats $150 that could go to the tune

Oh cheers thanks for the info, i will keep the doubles then. The only reason i got double was beause they are the original springs in the car and i wanted to make sure i was gonna be safe and not have any valve bounce. I also heard that the standard springs arnt really recomend for anything higher than 0.500 lift, im sure they would be ok but for how long.

Also its says on the crow site they need machining??? im not sure what they mean by it but i will have to give them a buzz to see.

good idea.

i spoke to wade cams and they reckon the standard springs will cope, just dont sit it on the limit for too long.

the 1673 has .484 int and .512 exh @ half inch lift, and they say that the stocko's will cope with anywhere up to .500, so its close....

ok i just been down today to see how much it will cost, its gonna cost me $325 to put the cam and double vavle springs in aswell as machining the vavles. With your car how are you gonna run the 1673? do you have the e-series rocker gear. The 1671AU cam is the equivlent to that one but it's the AU version

I also went to Cave Hill engines in Lilydale and they said they would do a full port and polish, put the springs and cam in and do it for $1800ish. Does that sound alright? He said i would gain quite alot with the port an polish as the AU heads dont flow aswell as the older models but they have more potential.

no its a standard au head, they are doing the 1673 grind on an au camshaft, only difference being a 115 lobe center as opposed to the 113 on the origional grind to suit the auto.

as for getting a port and polish its up to how much dough you have. personally id wait till my head gasket went to do that. but im pov.

the stock heads flow up to 320hp on a bench, so the cam shouldnt be taking it to its 100% limit.

with those mods and good tune engine should be around 240-250 hp. save the headwork for when you need to feel more rush then after that its bottom end rebuild. doing it in stages keeps the fun going i reckon.

yeah i had my engine rebuilt 15,000k's ago with ACL race pistons, head was recod aswell so thats gonna be along time before the head gasket to goes

being a roller cam, i wouldn't be to worried about taking lobes off.