[six shooter]

Hi every one, just signed on today, enjoy reading your views on pontiacs. I have a question concerning my 389 that I'm about to rebuild, I managed to over rev the engine and now I have a knocking sound at around 2000 rpm, It gets louder if I put a load on it. I figure I broke a piston skirt or stretched the rod bolts enough to spin a bearing, any way I'v been reading up on heads and what will work on a 389, I have a set of #62 heads and want to use them on my engine, I'm going to install a Comp 280 magnum cam 230@50 480 lift, My question is, what do I need to do to make this work, Should I change to a longer pushrod being that the heads are off a 400, etc.The car that this is going into is a 65 GTO,(original motor) I'm running a tripower, headers and a turbo 400, I'm swapping out the 3.08 10 bolt posi for a 12 bolt 3.73 posi, I'm going to go with a turbo 350 torque converter for a bit more stall, The jets I'm running in my tripower are 68's front and back and 63's in the centre, I live in area that is 4300 ft above sea level so you can imagine how much fun I,ve had making the tripower work. Any how I would appreciate any help on this project I'm about to tackle, Cheers!

[TheMonkey]

hey, welcome to the forum. you're in good hands here.

Originally Posted by six shooter

..... My question is, what do I need to do to make this work, Should I change to a longer pushrod being that the heads are off a 400, etc.....

sorry, i can't answer your question, but am surprised it hasn't been addressed yet. thought i'd bump it up.

[b-man]

When swapping heads use the pushrods that came with the heads, in this case the longer 9.145" 400 pushrod wil be much closer to what you'll need.

[Bill Eveland]

I did the same thing, 389 bored out to 400 and used the Comp 230/480" lift cam. I used the stock length pushrods for the newer heads. I also used the Magnum roller tip 1:52 rockers arms so I could adjust the valve train. You may want to replace the bottlekneck studs also with some BBC ARP studs.
I would at least run a 2500 stall for that cam. I'm using a 70 cast iron intake and 800 cfm Cliff q-jet. Also running a 3:90 gear with 28" tires. Havn't got to drive it yet with the 2800 stall or gears. I was using a 3:23, 26" tires and stock stall and it was a bit of a dog out of the hole.
I would at least add Arp rod bolts, but you would be better off with some cheap forged rods, you can those for about $250, money well spent.

[six shooter]

Thanks for all the info guys, Where can I get forged rods for a descent price, Have been keeping an eye on Ebay but no luck yet, Also I was leaning towards forged pistons, or is this over kill for a pontiac 389, I'v been reading so much about comp cams XE274H on this forum that I'm convinced this is the ultimate street performance cam. It's a toss up, Trying to figure out which cam to use can drive a guy crazy,Oh well I'll just keep on plugging away, Cheers!

[Bill Eveland]

Any of the Pontiac vendors like Pontiac Dude (Kens Speed and Machine) will have what you need. Stick with a Pontiac vendor in my opinion, they know whats best for your application. I also went with a forged 400 pistion, it was cheaper than the 389 cast pistons at least when when I bought them.

[red76TA]

definately use forged slugs, pontiac dude sells custom "light " pistons for a real good price but if you want to go with the regular speed pro's you can get them anywhere, summit is pretty cheap
the dudes website is http://www.angelfire.com/fl4/pontiac...chineshop.html

[66bonne]

For good pistons and good advise to go with them click on the "Ken's Speed and Machine Shop" icon on the right hand side of this forum.