No posi yet. I've got a '63 posi unit ready to go in, but I've gotta come up with a solution for the difference in spline count first, which probably means custom axles. That burnout was just a one wheel peel, nothing too impressive unfortunately. Most of the time I was shifting around 4500. Nothing too crazy, but doing that burnout it easily rev'd past 5k before I pedaled it.
Yeah, but I feel like a 4 year old trying to see over the dash!:laugh: Love the sound.... real smooth, doesn't seem to resonate or drone.
I love it!! Sounds tough. Nice note from idle and all the way through the rev range. Looks like a nice area you live, the tree colours are fantastic Inspirational.............time to get back to the shed. Thanks for sharing Andy.
Yes, it has a tough sound - ready to rumble. What are the toggles and light on the dash for - SP controls? Cheryl
LOL! Sorry Walt! At some point I do need to do something about the exhaust. It resonates really bad at about 800-900rpms - I think it's because of where the mufflers are located. Thanks! Thanks Cheryl! One toggle and the light is for the electric fan, the other toggle is for the SP converter.
Fortunately, you don't spend too much time at those rpms! It's SUPPOSED to sound loud at stoplights and idling thru parking lots! I love the Walker Dynomax's on my blue car.... they're pretty quiet, but still give a nice idle sound with the big Isky cam. The Magnaflows on my red car get noisy whenever I get on the gas a little.... kinda annoying. Gonna put some Walkers on it too.
It runs really good and sounds really mean. With the factory ST400 converter it has to idle at about 1050-1100rpms in park to maintain a decent idle (650-700rpms) in gear. That is honestly my only real complaint. That's probably something I'll address over the winter. I'm just now diving into tuning the carb and re-curving the distributor. It ran great but I can tell it's got more in it. It pulls about 10-11in of vacuum in park, but only 6 or 7in of vacuum in gear. I'm going to have to put different power valves in the carb since the original 6.5 PV's are probably partially opening when idling in gear. As far as timing, it's been set at about 14* initial and about 34* total. But that wasn't all in until around 4000rpms or so with the stock weights and springs. I'm shooting for the same initial and total figures, but all in at about 2500rpms, maybe slightly less. Also, in terms of vacuum advance, the Thumpr doesn't produce enough vacuum to properly operate the factory advance canister. So I'll be looking at either getting an adjustable canister, or possibly the replacement GM canister used in low vacuum situations. And in terms of city driving, no real complaints. Providing the idle is set high enough it idle's in gear at a stop light no problem. Definitely needs a little fine tuning, but that's to be expected with such a radical change.
Since the cam has 20* of overlap you may want to try more initial timing. For now just turn the distributor and work with the timing at low rpm only. Here is what Jim Weise had to say about timing versus valve overlap Paul
You have a nice car and it sounds great! When I purchased my 64 Riv last fall, I did not know what cam it had in it, only that it idled rough (500 - 650 rpm). After listening to some videos on youtube and your posts, I am certain that I also have a Comp Cams thumper but in a 425. It sounds the same and idles with the same lope. I am also having the same problem with the vacuum about 5-6 in at idle so I am interested in the low vacuum advance that you speak of so keep us posted. Right now I have my timing set to about 2-4deg initial but it has a hesitation coming off idle some times. Planned on playing with it more tonight. Not sure what my total advance is, I will check tonight. I have an MSD ready to run distributor with the lightest springs possible as I was anticipating not having any vacuum advance but after I added the new ignition system and richened up the Edlebrock Carb, I now have vacuum off idle in the teens. Woohoo! (At least I have power brakes while cruising, lol) However, I am still running without the vacuum advance cause of the way it bleeds off at idle and the idle drops out. I dont know what converter I have (possiblly stock?) And in case you are wondering, my exhaust is unknown too, all I know is it has short mufflers that look like a stock type design (rolled crimps on the ends) and they run all the way out the back. Keep up the good work!
I can't really run more initial without ending up running too much total. That's why I'm trying to get the vacuum advance figured out, since that would add roughly 16 degrees. That would be put me at about 30* at idle. John I'll look up that part number and get back to you. It's like a $6 part from Rock Auto.
The part number is 4V1053 from Rock Auto. This canister gives starts advancing at 3-5in of vacuum, and gives 16* of advance at 5.75-8in of vacuum.
If your actually running a Thumpr you need way more initial than that. Like Paul mentioned, at 14* I'm being fairly conservative. Since you have an MSD setup you have infinite tuning capabilities. Wish I had their distributor!
Yes, I do have a bushing to limit the mechanical advance if need be. Not sure how much it will limit it though.
UPDATE AGAIN! As of this morning (5/24), the GM place canceled my order due to no stock and a discontinued part. By chance I found the part number Rock Auto listed on Amazon from an auto parts store in Iowa. I again ordered 2 - and they already shipped it. Hopefully it's the right part when it shows up.
For those that are curious, I finally got around to tuning the carb and re-curving the distributor. Haven't had a chance to drive it yet, but it seems to have REALLY woken it up. Throttle response is incredible - rev's higher and stronger than ever. When I yanked the carb apart I was surprised to find high flow 2.5 PV's, rather than the 6.5's I thought were in there. I bought the carb used from a V8 member a few years back and thought he reinstalled the original 6.5's. I replaced them with standard flow 3.5's, re-jetted to 72/76, with 31 squirters. I used a Mr. Gasket advance kit. I used the weights supplied in the kit, along with one light and one medium spring. 14* initial, 36* total, all in by 2200 or 2300rpms. Still waiting on the new low vacuum advance can, providing it actually shows up, but that should put me at about 30* at idle, and 52* at cruise. First local cruise in is this Friday - itching to get on the road! :TU:
sounds evil man! as soon as we get my wife a new car we are going to pull the motor and tear is down for the rebuild. she has been driving the buick for three months she loves it just sucks gas. which thumper did you go with ? did you order it from comp? do they have lifters and valve springs for the motor?
I went with the Thumpr, not the Mutha or Big Mutha Thumpr. I got the cam and lifters as a kit from an online retailer. I think the company is on eBay and also has a website. I forget the name of the company though. It was a pretty good deal, and was on my door step within a few days. You'd probably have to get valve springs from TA. Comp doesn't have any listings for a Nailhead, although they might have some that would work. My motor was rebuilt not too long ago, and with a cam milder than stock, I figured the valve springs should be alright. I don't rev it very high anyways. I said good bye to mileage when I installed a Holley Double Pumper! I can still manage 10mpg or so on the highway but don't even bother to check - it would probably just make me cry. :laugh:
