Hello,

A B18 to B20 swap is pretty straight forward, but there are some differences that you need to be aware.

If you get an 8 bolt B20, you need to get the flywheel or flex plate as your B18 has only 6 bolts.

8 bolt blocks have metric threads for the 4 threaded holes to mount the bellhousing.

8 bolt blocks use a different crankshaft pulley bolt, but the crankshaft pulleys are interchangeable so just use the correct bolt.


Here are some tips to make your conversion go smoother especially in the long run.

1. Get your radiator checked and re-cored if necessary and don't cheap out on the radiator re-core, get at least a 3 row and I now will only use the heavy duty 3 row cores as it only costs about $30.00 more than the standard 3 row.

2. While at the radiator shop, have the neck for the pressure cap changed to accept a higher pressure cap and have the hose connecting tubes changed to the next larger size so you can use the larger size hose.

3. For better performance, you should get a later exhaust manifold with dual outlets and of course a dual lead pipe or get a header.

4. For better performance get a B20 distributor, preferably one out of a 1974 Volvo as it does not have a vacuum advance. Since I now longer can get rebuilt distributors right from Bosch, I am recommending the "123 ignition" distributors. They are pricy, but all electronic, including the advance. I have installed 2 of these so far for my customers and they have been running trouble free for over 6 months.


Hey George,

I used to use just the 7/8" plugs, but when 1 in my car popped out after a backfire I went a step further and added some simple plates on top of the plugs, which is the way I do all of my customers now.

--
Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90501