school me on 389's
 

I am looking to make my 72 Lemans more street friendly. Right now it has a 455 and runs 11.70's at 3800lbs. Going to make it into a cruiser for road trips.
I have been looking for a 400. I have a buddy that will give me (yes free) a 389 to build for it. I am not familiar with them.
Is it basically a 400? Are they good engines? I want to build it mostly stock with an 4 speed auto. Looking to make some 500 mile trips.

What year 389?

Anything ‘63 and earlier you will want to avoid because of the bellhousing bolt pattern on the earlier engines being difficult to adapt to later transmissions and bellhousings. Starters bolted to the bellhousing on ‘63 and earlier setups, there was no provisions to bolt them to the block until 1964.

A mostly stock 389 will get you down the road just fine, parameter wise it’s just a 400 with a slightly smaller bore size (4.0625 vs 4.120”). Later 389 heads are small valve (1.92”/1.66”) and all have press-in rocker studs and have no pushrod guide plates, just precision milled slots in the head casting to guide the pushrod. Worn out pushrod guide slots are not uncommon, so keep an eye on those.

Of course any 400 head can be used on it as long as you use 400 pushrods and rockers, making it easier to have the preferred screw-in rocker studs and guide plates. 400 pistons to match the 400 heads should be used. The 389 heads had the valves in a different location than a 400.

Don't know yet. Thanks for the information.

The 64 Block may be stronger than the 65-66 blocks. They were still a couple of years away from being retired for the 400 blocks. And as was mentioned all of the later driveline parts, flywheel, bell-housing, starter, heads bolt up nicely.

But any of those 3 years: 64, 65, 66 are fine for a street cruiser.

Tom V.

If you bore a 389 block .058", you have a standard bore 400.
 

Same 3.75" stroke.

Early 389s had a short crankshaft snout. Make sure that yours is long enough for your choice of harmonic balancers.

Sonic check it before boring, obviously, but most 389s are plenty thick.

Use 1967-up heads so intake manifold choices and valve sizes (2.11/1.77) are better.

We've done two this way and were VERY happy with the results.

Besides, FREE is good!

Short snout cranks wont effect use on a later balancer assm.The lower gear seats on the crank,I have used many short snouts on many of my builds.Tom

The first thing you should do is to check the lifter bore clearance.

Why not just detune the 455? Pump gas heads, cast iron intake and smaller cam in your 455 would make it road worthy.

Beat me to it !

Can use even less gear than with a smaller engine, because of having more low rpm torque.

With a correctly built & geared 455, it should cruise at not much above a fast idle.

I think the FREE 389 engine originally started this thread.

Tom V.

Need more information about the 389. Some of them will have a CR from the factory which may not like today's gas.

Stan

Build the 389 with compression around 9 to 1 and if you really want a cruising engine the stock heads will be just fine. These engines in stock form pulled 4000 lb cars around just fine with a 2.69 gear ratio. Be truthful to yourself about what you really want. I drove cars with 389's when they were new and they were not slugs even in 2bbl form.

Stay away from the 66 389. They had a LOT of overheating warranty issues.
Its also the reason the 67 400 is a great block. They have extra thick cylinder walls for the first year of the 400. Could not take a chance.
I grew up with a 66 Catalina station wagon. Took us across the country twice. It died of a cracked cylinder wall.
Guess Dan Whitmore was right.

With any motor your going to build up if it's not already your going to want to get it Mag checked for cracks, but as I recall most of the over heating failure they had in 66 was in the B body cars ( GP and Bonniville ) with AC that restricted air flow.

Not many A body new car buyers in 66 shelled out for AC!

Free ???
 

Is free always the best price ? :confused:

With all the negatives guys are putting out here, it brings the question to me, is it always best to build an engine, just because the initial cost is free ?

I think of all the 350 Pontiac engines that have been offered for free, or at least dirt cheap. Some of those owners have reported that they had no takers & junked blocks.

Why was that ? No, it was not because a correctly built 350 is no good & won't make any power. I can name a Stocker & 3 Super Stockers that have run 10's with 350 Pontiac power.

So, it might be that this free 389 is in the same boat as those free/cheap 350's. It just MIGHT be a better buy to buy something else as a core to build, even if it costs a few hundred.

If I were gonna build a mild cruise engine, I'd wanna start with a good 400 block that has all 5 motor mount bolt holes. And NOT a "557" block. And if I used iron heads, I'd want 6x-4, or 5c-4, or at least 6x-8 cut down some, to increase CR.

Would definitely want a Q-jet carb & dual plane intake.

If you have one of these built just right, it should do exactly what you want. BUT, if for some reason you don't like it, you have something that lots of guys are more likely to buy, should you decide to sell, than a 389. I'm guessing that the 389 is just not in very high demand right now.

But hey, that's just my thinkin.

https://forums.maxperformanceinc.com...d.php?t=836191 No problems with this one whatsoever. Runs at 185 deg with the AC on. Hundreds of thousands of these engines ran a collective millions of miles.... I'm not understanding why one can't be built as a good cruiser for the street and run for the next 30 years for the way that we use these cars? I will point out the only limitation i found when building mine was on the shelf piston selection is a bit limited, but there are a few choices especially for a street engine.

Going to have to slip a new cam and new / reworked heads new pistons rings, bearings in that free 389

Can slip in a new cam install new / reworked heads then a stock intake you probably have laying around in that free 455

Maybe so but the first car I bought new was a '67 327 Camaro (coupla months before Z-28 came out and the 350 had a bad rep already for oiling problems) with 4-speed/console and gauges/AC. All of my cars have AC.

ps autocross trophies were never very big.

pps nothing wrong with a 350 or 389 other than Pontiac V8s have always been heavy and early cranks were a different length than later. Just easier to build a 400/455 even though I always liked a 421/428 with the shorter stroke. Think there is still one in the back garage...

http://performanceresearch.us/padgett/cars/camaro.jpg

Chances are the block will have to be bore oversized. If it sonic checks out you can take it to 4.120" and use 400 std pistons. Had one that had this done to it many years ago.

Stan

Pistons
 

Times & prices have changed. It seems that the cheap SP forged pistons are history, unless you can find a set still on a shelf somewhere.

From what I can find, in the last few minutes, good forged 389 pistons will run about $600 + tax.

DSS has the 389 covered. They make 'em for early or late type heads. Also offer 4032 or 2618 alum.

https://dssracing.com/Pontiac-piston...55-stroker.htm

IF your block will go to 4.125, & you wanna take it that far, you MIGHT be able to find some early Olds 455 std bore pistons. This has been discussed here before. These dish pistons should work with early or late heads.

SP forged are # L2323F std. Here's a set + moly rings, for $385 + tax.

https://www.ebay.com/itm/17105739891...gAAOSwr41XH4BP

The SP number for 400 Pontiac std bore forged piston is L2262F std. But good luck finding a set. It appears that SP quit making the 400 & 455 Pontiac forged pistons. Summit currently shows that they can special order a set for you. But, I suppose that would depend on whether or not SP actually has a set in stock at one of their warehouses. Price: $456 + tax

https://www.summitracing.com/parts/slp-l2262f

This place shows to have a set + moly rings in stock, for $410 + tax & shipping.

http://store.enginepartscenter.com/p...0784-p933.aspx