cam change?

[clutchdust]

to get a little more juice out of a mostly stock block/head, is a cam change the only option?

i do alot of SBC stuff and with that being an OHV configuration, i can play with cam lift and duration with different ratio rockers. i don't see any way to do something similar with these motors. there'd have to be a way to move the cam toward the rocker pivot or vice versa.

at $500+ for a cam package, it would be nice to get something a little cheaper if your not looking for alot of cam.

[zman525]

Im kinda in the same boat here... i was investing in a stage 3 cam but i dont really think its to necessary... and i would much rather not spend that much money! im gunna watch this thread closely

[beandip]

If your '73 still has the flat tops , remove them , for starters and find a set of round tops. I installed a ignition from a '79ZX complete with the coil , this was a big improvement in the driveability of the car. From there it's bucks . A 260 cam has the highest lift Nissan ever put in the Z , if you want to go that route . One improvement that isn't engine related is to change diff gearing. your Z if it has a manual trans , it has 3.36 to 1 gears in the diff. changing to a diff from a automatic , a 3.54 ratio , will give you more off the line. That is an option. A cam really just raises the Power band to a higher RPM for the most part . Then if you want the engine to breathe better at the higher Rs then the headers and larger dia piping is in order . This sacrifices low end power , which if the car is for street not track its really backwards , for street driving . Not many of us drive around spooling the engine to 5K all the time. But if this is your thing then it's there for you to try . my 5 ¢

[kenz240z]

Hi Gary, like Beandip says, if you have the stock flat top carbs on your '73, change them out to a pair of round tops. Then change the differential to a higher gear ratio. You may consider looking for a 3.9, 4.11 or higher ratio differential. I can't recall if these are all available as an R180, or if you would need to do an R200 swap. Do a search on this, it's been covered in depth before .

If you are looking to increase the horsepower output of the engine, then you might want to investigate adding a turbo :rambo:. The hybridz site might have more info on that. This option could get expensive .

Another thing to try might be to get a 4bbl intake and a good 4bbl. Most of the ones I've seen use a Holley carb. But, I imagine a linkage could be fabricated to work with a Q-jet or Carter AFB. This would allow you to tap a little bit into your SBC background... But, this would probably cost about the same as a cam change, probably more :eek:.

[clutchdust]

Another thing to try might be to get a 4bbl intake and a good 4bbl. Most of the ones I've seen use a Holley carb. But, I imagine a linkage could be fabricated to work with a Q-jet or Carter AFB. This would allow you to tap a little bit into your SBC background... But, this would probably cost about the same as a cam change, probably more :eek:.

for simplicity, tunability and availablity sake, this is what i have in mind. probably going with the arizona speed intake and a 390cfm holley. an MSA header should complement that nicely. once the intake and exhaust are up to the challenge, i'm just trying to figure out how to get more air charge into the chamber. you know, the fundementals of hotrodding, more air/fuel in, more power out.