68 power question

[mcmasterson]

I recently acquired a '68 riv.  All original. Had carb rebuilt, new distributor.  It's very clean and runs great. Starts great, idles smooth and no hesitation. It just seems to not have the power it should.  I own a 63 and 75 riv as well and both of those seem to have more take off power than the 68 which holds more HP than the other 2.  It definitely wont spin the tires.  Just curious if this what it is or I need to look at doing something else?  I'm not expecting it to be a Viper or anything but just curious if perhaps upgrading to a different gear ratio would be beneficial?

 

 

[JZRIV]

How many miles on the engine? You could do a compression check which is not a bad idea if for nothing else you have a baseline for the future.  As far as spinning the tires,  with a 3.07 std differential that's going to be a challenge. The best running  67 I ever had would not spin the tire going forward and  this car was light weight due to stripped down zero options. Also the 67s had the switch pitch converter. Even though it didn't spin the tire it was fast out of the hole for a big car and even faster once  that mass got moving much to the surprise of many a contender.

Carb can make a BIG difference. Not sure how your carb was rebuilt or who did it but if someone  simply put a "kit" in it, it could still have issues needing addressed. I have found its best to send to one of the quadrajet experts for rebuild.

Edited July 23, 2020 by JZRIV (see edit history)

[60FlatTop]

Put it in neutral on a level floor. If you sit in the driver's seat you should be able to make it roll just by pushing with your foot on the garage floor.

[70rivme]

Congrats on the new Riv! I will start by saying that I know exactly how you feel and had the same feel with my '70 when I bought it. Started great, ran good but would talk back and refuse to work if I asked it for the power I thought it should have had. I am going to list everything that I did that without a doubt helped my car run better and smoother but at the end of it all I feel it should still have had more power. 

 

*Check your basics; fluids, brakes, tire pressures, tire condition, timing, condition of tune-up parts especially the fuel filter

*Make sure you are running fresh fuel and the higher octane fuel at the pump

*Check your fuel pressure. My 1970 has an in tank electric pump while the one in your car is mechanical. My car benefited from a new pump and ran noticeably better. 

*Convert the points to a Pertronix ignition if not already done. 

*Check your exhaust for anything wrong or out of place. One of my mufflers was pretty much collapsed from something hitting it.

*Try a different carb. I bought a newly redone QJet that was correct for my engine from a forum guy who sells them on eBay. Noticeable drivability difference.

*Check your rear end ratio. My car came with an open 2.78 stock, so I converted to a 3.08 posi and hands down this has been the best upgrade yet.

*My car came with what could have been the original bias ply tires. It benefited greatly with a swap to radials.

*Check and or change the thermostat too.

 

That about sums up what I did to create a better driver and get the power level up. Since all of this was done there is now a mild 464 BBB with headers and 2.5" exhaust going in with a fresh Turbo 400 and JW 9.5" torque converter. I'm hoping this seriously cures that lack of power feeling!

 

Good luck!

[mcmasterson]

Thanks for the replies.

 

Car has 83k miles on it.  The guy who did rebuild is a very good mechanic with 40 years experience so I know he did a solid job on the rebuild.  

It's got new pertronix ignition, coil, distributor. It has glass packs for mufflers that appear in good shape with no leaks. The mechanics did a thorough once over while on the lift. Havent considered fuel pump.  Would a bad one cause general inconsistent or rough running?  That would be a cheap replacment.

It has newer wires and plugs too along with almost new radial tires.  I guess it sounds like maybe going with a new gear ratio might be the best bet.  I dont want to do any other molestation to the original engine.  Thanks for the input!