I know this is a thirdgen tech board but i just wanted to see if anyone out there has one of the old 6.6's. I am currently looking to purchase one that ive seen for sale. Just wondering if theres anything common about cars that has a tendency to be bo janked, and what kind of power i can get out of the motor.

 

find out if it's got the Old's 403 or a pontiac 400, the poncho has more HP and torque than the olds, and there's more aftermarket parts around, but if your looking for a daliy driver there both reliable, if well maintained abit on the heavy side though, since olds and pontiac both don't have a big or small block- a pontiac 350 is the same size as a 455 and all the parts (execpt pistons and crank and possably rods) are the same.

 

The poncho 400 motor is a strong runner with a little massaging. If the motor is stock you can run big block chevy rocker arms to help it rev better. The stock bottom end will take nitrous without any mods. The only weak points on the motor are the water pump block interface which is hard to seal and corrodes fairly easily if you don't keep up your coolant mixture, and the valley co er tends to leak oil if you don't let the gasket sealer cure completely before running the motor. I ran a ram air III 400 in my 71 bird and couldn't keep tires on it because of the torque it produced. A friend of mine had a 78' T/A with the 6.6 plumbed with nitrous and we had some very close races. Good luck if you pick up the car.

 

Get a 78 and it'll have the pontiac 400. The 403 cars were all auto a,d the bottom end of the 403 has windows in the main webs making the engine suck for anything over 5500 rpm. That's a shame too, because the 403 has huge bores and a short stroke and could be turned into a real screamer otherwise. Look for a WS6 while you are at it. I had a 79 Ws6 that handled great, but it kinda sucked powerwise even with extensive work. If you like the 79 look, just get a 78 and add the 79 stuff to it. You'll be much happier with the 400 poncho mill, that is unless you find a nice 403 car, scrap the underhood anchor, and drop in a 455

 

I had a '76 TA with a 400 in it. The most reliable car, I've ever owned. It got 12mpg and was a tank. It wasn't that fast, but very nice car I think. It sat for a few years before I got it, put in a new battery and started right up.

 

building a Poncho 400. You'll love the torque. main thing is the heads... it should have 6x heads. 6x4 are the heads you want. you want the screw in studs... throw out the 3/8 bottleneck studs and put in BBC studs for adjustable valve train. Thats the bad part of Pontiac heads.

 

I just got a 79 TA with the olds 403, i say you should stay away from the 403 unless you just want to stay stock, but if you want to really beef one up you should go with 400 and the 4 speed. there is a lot more mod potential.

 

Nice thing about a 403 is that a 455 olds will bolt right in. Mega torque. Keep the 2.73s and it should be pretty awesome.

 

same is true for the poncho 301,350,400, and the 455, exteranally (ex.301) there all the same and they all have the same engine mounting and bellhousing patteren.

 

A comment was made that there was no big-block or small-block Olds engine.

That is incorrect.

The 330, 350, and 403 are considered small-block Olds engines.

The 400, 425 and 455 are big-blocks. There also was a series of Olds V-8 engines that began in the late 1940s but generally the Modern Olds engine began with the 330 in 1964 (or thereabout).

The intakes on the big-block Olds engines are wider than those on the small-blocks.

The crankshafts of the big-blocks have a larger main bearing size, also.

The heads will physically interchange but performance will depend on the version used.

There are some other parts that will interchange but you have to be careful.

The big and small block LOOK similar but the big block is physically larger.

The big-block Olds will bolt in place of the small-block Olds, easily, in MOST cases, but the extra width can cause clearance issues.

jms

 

Take a magnet with you when you go to inspect the car. The rear quarter panels are known to rust out above the wheel opening. Make sure a previous owner hasn't "fixed" them with bondo (the magnet won't stick to bondo). The flare stlye ground-effects in front of the rear wheel openings tend to trap water, causing the sheet-metal beneath to rust out (you have to remove the plastic flare to check). And most importantly, pop the trunk, pull up the carpet and inspect the rear shock mounting areas. They have been known to rust out. When that happens, the shocks can push through the floor-board - not a pretty sight (happened to a friend of mine).

Manual trans cars got the Pontiac 400. Auto trans cars got the Oldsmobile 403.

I had a '79 TA with a 403 that, with 2.73 gears, ran 14.20's @ 101 MPH (going through the traps in 2nd gear). It was so concistant that I was runner up (2nd place) at the '92 Milan Dragway Highschool Nationals.

 

Personally I would go for the 403 in the '79. I used to have one and it ran like a raped ape. A friend of mine had a '77 T/A with the 400 in it and my '79 would out run his easily.
It is true, however, that the 403 is not suited to hi-perf use because of the main webs being too thin. But still there are a few things that you can do to get a few more ponies out of it.
On mine I installed headers (A pain to do) and true dual exhaust with a pair of thrush turbo mufflers.
I cut the back out of the shaker hood scoop, and installed a "scoop kit" from J.C. Whitney that consisted of a plate to cover the hole mounted to a long jack screw that was turned by an electric motor controled by a switch inside the car to open and close the backend of the scoop. Also, inside the scoop I removed the stock air cleaner and put in a 7" velocity stack with a built in foam air filter and did some tweaking with the secondary butterflys to make them open a bit faster.
It had a 140 speedo that I pegged regularly and was a joy to drive.

One thing to keep in mind if you do get it, the exhaust manifolds on the 403 are the same as the 455, so header gaskets will be easy to come by (don't ask how I know).
And yes, the 403 is a smallblock Olds engine, revs up fast too.

~M~