firebird 400 swap

[jpwesly031]

i need a walk-through on how to install a 400 (w/ 5 engine mount bolts and 11bolt wp) into a 67 firebird that was orginially equipt with a 326

[TT402LS1]

I believe all Pontiac V-8's are the same size, and all bolt in the same. I could be wrong though.

Ron

[wick]

If you have a five bolt block you can use your original motor mounts. And all of your accessories should bolt up as long as the heads have all of the mounting holes. You shouldn't have any problems.

[Goatman]

Its a bolt in deal. Everything is the same.

[jpwesly031]

"In addition 1966 and earlier blocks had 2 freeze plugs on each side of the block. 1967 and newer had 3 freeze plugs per side.
These blocks had 2 motor mount holes per side.Starting in 1970, most blocks were cast with 5 motor mount holes with the mounts using 2 bolts in line with 1 higher up in the middle.Some 1977 and later blocks only had 3 holes that used the newer mounts."

the 400 block im using is a 71 with 5 mountnig holes. does this mean i can use the 67 326 engine mounts and just use 2 holes?

[Goatman]

If you're not going to put alot of power to it.

But why not just buy new ones? They're not expensive........

[MonzaRacer]

One thing to watch for is the diameter of the pilot on the torque converter.
I built a 400 for my 69 Executive and the crank was an ealier model crank and the centering hub on the converter had to be ground down some.
the hole in the back of the crank should be measured and make sure it matches your converter, too big wont fit, too small and the converter wont center good and you will get vibration.
Good luck

[sporter]

When I swapped the 326 in my '67 for a '74 455 I had some issues with the water pump pulley. The later style 11-bolt water pumps come in two different lengths. You simply need to match the right pulley to the pump you have. Just don't sell or throw anything away until the pulleys and brackets are all lined up. :)

[406 Q-ship]

A 400 of 1971 vintage will be a bolt in, use the mounts from the 326 along with all the accessories brackets and pulleys. Sometime around 1969 pontiac changed it's accessory pulleys and brackets, well they don't look all that different than the earlier stuff. I would put a good size radiator in the car, Pontiac run hot and you are upping the size quite a bit.

[Hammered]

The crank register size change occurred in '75 or '76 so you don't need to worry about that. Use the timing chain cover from your '67 and you won't need to mess with finding pulleys and all to match up. If your '71 came with waterpump and crank pulleys, your '67 alternator and power steering should work just fine.

[jpwesly031]

right on guys