I am not quite there yet but I think I need some help. I have a mildly built 455 in my '70 Riviera that was running through manifolds and a stock style exhaust. The engine has very minimal run time as I had an oil pan leak that I wanted to take care of so one thing led to another and the engine has been out of the car for 1.5 years now. I will be getting this car reassembled hopefully in the near future except this time around instead of manifolds it will be running TA shorty headers into a 2.5" exhaust system. If the car ran good with manifolds for the short while before pulling the engine out, can anyone comment on what I can expect running it with headers and a 2.5" exhaust? Will there be noticeable power gains, will the timing and carb require tweaking? I'm running a 780CFM Quickfuel carb if this helps at all. The Turbo 400 will be rebuilt and more than likely include a JW 9.5 converter and be installed with the engine as well. Thanks for any input or suggestions, appreciate it!
I don't think you'll need to do anything. I wouldn't touch anything. If you get a wide band O2 gauge, you'll be able to see if you need to tweak jetting or not. Make sure the timing is correct. If all that means to you is initial timing, read this, http://v8buick.com/index.php?threads/power-timing-your-buick-v8.63475/
Cap'n Oblivious sez remember to prime that oil whirler a minute or three before you turn the big block music to 11.
With my 67 Riviera and it’s 430, it was stock running 14.69 @ 93.21. I put in a mild cam (219/238 .490/.453 lift), a 12” switch pitch converter, and the TA 2.5” exhaust with shorty headers. My time has since dropped to 14.02 @ 98.49 and there is certainly more left in it. Probably had 13.8s in it on good weather and traction days.
Good info, thank you! The man that built the engine supposedly rebuilt the distributor and worked all the magic that would make the distributor work with the engine/car. I guess we will see when I check it.
This is now on the agenda before it gets put back into the engine compartment. Thanks for the reminder Cap'n Obvious!
I was sort of happy, I then added another 100 horsepower in the form of ported Stage 1 heads, a much bigger cam, and an even larger quadrajet.
If I can run high 12s, I will be happy. That means only two 2nd gen Rivieras are running 12s on the entire East Coast, to my knowledge.