Switching to the 4.1

[bullet87]

Can anyone give me any information on the process of building a 4.1 production block and putting it in a 87 Buick GN, like what is required and any other links to people that have done it and links to pics.. Thanks :applaus:

[ledzeppac]

http://www.turbobuicks.com/articles/4point1ForCheap/

[Sixgun86gn]

Baffled 14 bolt oil pan and timing cover.Drill and tap 1/2 pipe thread hole in front of block for turbo drain(real easy to do in the garage).Use all the 3.8 peices left.I used my 3.8 flywheel and balancer and they worked just fine without any balancing.I built the shortblock for around $600-$800.

I suggest using a slightly bigger cam than you would in a 3.8.Also make sure the fuel system can handle the extra cubes under boost.There is a difference.

Hyper pistons can be bought for $200,forged for $600,or do like me and find some good used ones from a stage 2 and use them They only cost me $150.

The 4.1 conversion is a very basic swap and can be done without changing alot of parts.I have had no problem with the same chip I used with the 3.8 because I could add fuel through the translator.

Car went a best 1/8 of 7.17 on 93 pump and 16#,best 1/8 of 6.8 on race gas and 20#. Weight #3550.The 4.1 can make lots of power reliably.