since it's the time of constant rain up here in seattle, it means it's time to tear the A apart and take care of a few issues. need to completely rebuild the motor. here are the specifics of the car: 31 tudor. 1960 pontiac 389 topped with 3 94's (never did get these 100% dialed in) built th350 behind the motor. rear is a 10 bolt posi with 3.73 gears. this motor is really loose, but still moves the car like nobodys business. i don't want to build a motor for the strip. i want a good healthy reliable motor. shit, straight from the factory this thing used to put out over 300hp. what suggestions do you pontiac gurus have for this build? pistons, cam, head work, etc...... let me know if y'all need any more info. TIA
what is the head code?block code? head code is on the ehhaust ports, block code is on the block above the water pump housing on the pass.side. gotta know this stuff for purposes of internals.
Hey.. Go to my web site... sorta spec'd out my Pontiac, may give ya some ideas. Questions? e-mail me Pontiac Slim
I wouldn't go nuts with it.just rebiuld it and go thru it and freshen everything up.gasket match everything.mill the heads 10 just to true them up and a mild cam with a little lope to it.these things run like a bat out of hell anyway.don't over do it with a biggest cam you can find.I just got rid of a car that had a 68 400cube poncho with a set of 13's on it and a 67 tri power intake and a ram air cam. all pontiac no aftermarket crap and it would fly not 2 many thing in town could come close to keeping up with it.
yeah, i don't want to get crazy with it. just need to know what parts are going to work well together. the thing doesn't hook up as it is, with its 16x6.00 bias plys in back.
When I rebuilt my 60 389 I just went with flat top pistons and kept it simple and stock. They came with such HIGH compression out of the factory and it's going to be my daily hack that I didn't want to pay thru the nose to run it. I also picked up a tripower set up for it and will be running ROTchester carbs. Nothing fancy. Brandy
if you are having a bad tire burning problem you could go with a decent aftermarket cam that would move your power band up to mid-to high range and keep with a low stall just enough to let it idle.it would be more of a some what of a dog out of the hole but it would be bad ass high mid to top end.but alot rougher idle and bad gas milage.or stick with a stock cam and switch the 373's for 308's.it's still going to make the tires go up in smoke but by switching one or the other or both it will make it easier for you to control the burnout.not sure what you need to know. are you wanting to know the whole run down for a rebuild or just suggestions on what should be put in it thats not in it stock now.if there is a big ridge or scratch's in the holes punch it out 30 over.use the stock stuff if you can if it doesn't need punched out just rering the old pistons.if you need it punched just go with a set of 30 over TRW forged .gasket match the ports use cam of choice.if you want it to idle fair and have ok gas mileage and responsive at idle buy a new stock cam for that year motor or if you want that bad ass lope and more power go with a crane cam with same specs as a ram air III.if you really want it to sound like a dragster on nitrous go with crower beast cam.one of the biggest you can buy over the counter.if you go with the beast you will need at least a 3500 stall or use a 2500 stall if you want to bog it down enough to try to get some grip on the back tires.the pistons don't much matter in a poncho as for making power the head is where you get you compression from on them.that 389 has enough compression to run what ever cam you want already.
the car has a 2500 stall in it already. i guess what i'm really looking for is cam suggestions, (which you covered) and maybe piston choice. i thought i read somewhere that you can punch these out the block to use the 400 pistons. is this true? any advantages with those pistons?
While it's true that you can bore a 389 .060 and install standard size 400 pistons, Pontiac relocated the valve reliefs when they redesigned the heads in '67, so if I were you, I'd buy .060 pistons for a 389 and avoid the possible valve/piston carnage that could result from 400 pistons, especially if you're planning on running any kind of valve lift. I've seen some sets of "universal" replacement pistons that had both sets of valve reliefs, but they were pretty crude--they looked like I made them in 8th grade metal shop.
My '63 389 has been bored and uses dished 400 pistons, Crower cam (60916 I think), factory heads freshened, stock 4 barrel intake, Edelbrock 600 cfm, and stock log manifolds with duals. Very pump gas friendly but it still moves the '63 Catalina around easily. One of these days the 2.69 pegleg and Slim-Jim will get upgraded to 3.23-3.42 posi and a TH400 with a stock converter. You might want to check out the Comp Cams XE256H or XE262H, smooth idle with lots of torque and good up to about 5000rpm. Nice street cams.
one more thing.if you can get by with a 30 or 40 over bore you should go with that.these poncho's are getting harder and harder to find so if you can keep from cutting the block out to the max, then you or someone else later can punch it one more time for a rebiuld .never know someone in 20 years may be tickled to death that they can go another 10 thous/ to get another rebiuld out of her.going 60 and not 30 will not hurt you with HP.you are not going to make that much more HP by going all the way with the max over bore.
hey guys, ray nichels passed away a week ago. nichels engineering built alot of nascar and indy engines during the 60's. i heard old timers reminiscing about the shop and how one engine dynoed 30 hp higher than the rest. after tearing it down to investigate, they found someone had put the pistons in facing backwords. i believe it was a 421. i didn't hear the rest of the story, but it was magical listening to them.
Sorry it took so long to reply...got busy. the double releif pistons are good for a street driven car that won't see above 4000 for more than a few seconds,and they weigh a ton. butler parformance has some nice ones at a good price. I totally agree with the ram air three cam--it is what I use in my 389 tri power. be sure your builder knows ponchos. the thrust bearing is right in the middle of the crank and if he does not get top and bottom right, is will turn it into chore boy in your crankcase. poncho rods pretty much kick ass, so I wouldnt mess with them much. a little balancing really wakes one of these up. it is money well spent. pioneer makes a kick ass harmonic balancer that is sfi spec,and has good timing marks...and is c-clipped to avoid high r.p.m. distruction. a carter fuel pump(mechanical) is more than adequate for supplying the go juice. the only other thing I can think of is to be sure the cam plate makes it back onto the motor,along with the stock windage tray. simple little parts that make all the difference in motor life.
For an early 389 I'd use the factory '068' cam that came in 389 GTO Tri-Power engines as well as 400 Ram Air/HO, 428 HO and 455 HO engines. The .407" lift 068 won't overstress the factory press-in studs and will work without having to change anything in the valvetrain. Miles of trouble-free driving will be yours using the factory parts that GM designed, plus it'll scoot down the road pretty nice.
'59 and '60 motors are a little peculiar in that if you mess with the cam, you mess up the valvetrain geometry. I have a '59 short block and rebuilt heads sitting here I have yet to assemble for that reason - in college, still learning, I changed the cam out for a hotter one, then I find out later it screws things up. I really want to put new top-end stuff on it anyways instead of reusing the old, so it's been waiting for me to find out how to determine what will work on it. You'll note that Kanter wants a bunch more for the 59-60 pushrods (like $8 each instead of like $2). I can re-post on the pontiac-1950s yahoo list or check the archive for more specific detail, but it has to do with the rocker arm ratio or something like that. If I were going to do it again, I'd have punched it .055 instead of .030 and gone and pulled a set of later heads and run those instead. Even '61 heads, for that matter. As it was I had to replace the one head twice, one that came on the motor had a cracked exhaust seat you could see bigtime, second one had already had the guides changed once and one valve jammed in the guide - the guide would come out before the valve would. A few tricks you can use on these - find a 301 and part it out. HEI fits if you want one; front cover is aluminum and a bolt on (unless you use the 55-57 front mount, it's not strong enough to stand up to it) and if you still have a cannister filter, the 301 screw on adapter also bolts up. Oil pan will also fit if someone needs one. By the way, how the heck do you get a TH350 behind a '60 block? Someone start making an adapter that fits the 55-60 pattern, finally? Machine your own? Last I knew, this wasn't an option because there's no place to mount the starter.
thanks for all the good info! got my adapter from wilcap. comes comeplete with crank adapter, flex plate, and trans adapter, all hardware. moves starter to passenger side, using a mopar mini starter. IT'S A VERY NICE SET UP!
Something for you to check out. I seem to remember that, if you switch to '61 or newer heads, your intake manifold may not work any more because of some water passage changes. It's been 42 years since I built my '59 389 for the dragster so I may be all wet !
Yep, if you change the heads you'll need a matching intake. 61-64 should be the same. Was it me I think I'd just get another motor and build it and keep running the one I had until I had the second one done, I think.
I built a ton of Pontiacs- try the Comp 268H- noticeable idle, great torque, 18" vacuum, easy starting Pontiacs love solid cams too, so a similar grind in solid flat tappet would be neat duration- I would not go over 225 or 230 intake duration at .050" get a good pair of headers- Pontiac exhaust ports are bent like a horseshoe, they need all the help they can get I run a 455 Poncho 60 over, with RA V heads
Part #1: Melling 10540 oil pump. Once you start upping the power you need to make sure you have the right oiling system on a Poncho. Call the Butlers and get the right combo of pump/shaft. I wouldn't go bigger than the 068 cam with those heads UNLESS, you pin the studs or replace with screw in studs. The Summit 2801 would be a good cam for your setup also. 1.65 rockers require grinding clearance for the pushrods. Most people overlook this as the high-ratio rockers seem to be a bolt-on. You already have a big enough converter for a mild solid cam. Do not fear the solid cam! switch to screw-in studs, put restrictors in the lifter bores, and install a Lunati 40706. It has a mild lift but it's ground 108/106 for a wild idle. Your car is light enough for it. This cam is guaranteed to scare the shit out of everyone within 1000'. Steer on over to the performance years forums; http://performanceyears.com/ for the best Pontiac info. Get a few opinions.
excellent info and ideas guys!! keep em coming! i love the parts numbers, gonna be very helpful. ok, here are a few things you all touched on: finding a second motor and building that one while the first is still running. well that's not an issue. the rain and snow have come to seattle, so the A wont see the road again till april. plenty of time to pull it apart an put it back together. newer heads... nope, gotta run the originals, with a little work to em, cause i went through hell and high water to find the offy intake and rebuilt 94's. headers? straight pipes right off the heads, maybe 24" long.
Since you are going to stick to those guidelines.....I'd just refresh the motor. You want something for daily use if you so choose and let's face it, driving a petrol pig gets REAL tiring REAL fast. Your model A doesn't weigh as much as my fat lady and I'm just going with a freshened 389 with tripower. She'll move her big ass easy enough with just that. You won't need to change the pressed in studs either. They really are sturdy, not like you're building a rocket ship. I've had plenty of Pontiac nuts tell me to change mine.....not gunna, no need. I'm not running that extreme of a set up and neither will you. Draggin Gto has a REALLY good point tho.....use factory Gm stuff, fancy parts are like fancy women.........HIGH MAINTENCE! Brandy
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