Remove the distributor cap. Remove the hose to the vacuum advance. Remove the two screws holding the vacuum advance on. Install in reverse order.
800rpm manual transmission, o degrees advance 1200rpm automatic transmission 4 degrees advance
Everything should bolt right up.
the regulator is inside the alternator and yes you can take the alternator apart and just replace the regulator.
Assuming you are running a point type distributor a Pontiac typically likes 12-14 degrees initial advance. This is also a good starting point for HEI.
with the engine operating temp and (if applicable) the vacuum advance undone and the vacuum line plugged up. it should be a 14 degrees before top dead center
you should be able to unbolt the motor from the firewall on the passenger side of the car
One place to get parts for a 1970 Pontiac Grand Prix is at the website Stock Interiors.
Which 454? The LS5 and LS6 are two VERY different engines even though they are both 454's. Timing specs are different as well. 8 degrees before TDC at idle will work for either, but may not be optimal.
There were 2,170 convertible GTOs in 1970.
A 1970 Pontiac Service Manual will have this info in it. You can find them on Ebay or one of the literature places on the web.
Weight on my Pontiac LeMans Sport registration is 3800
There are many places one can go to to purchase a Pontiac 1970 GTO. The best place would be your local Pontiac dealership to help locate you one. You can also try AutoTrader.