View Full Version : 4.1 Vs 3.8

07-27-2005, 12:19 AM
I Have A 150k Mile 1987 Gn Motor In Need Of A Rebuilt My Brother Just Gave Me A 1984 Totaled Regal With A 4.1 .
Can I Rebuilt The 4.1 And Put All Of The 1987 Gn Parts On That Block ?
If No Why Not?
If Yes, Will More Cubes Equal More Power?

07-27-2005, 09:53 AM
4.1 will have a 14 bolt oil pan vs. the 20 bolt pan.

Other than that, here's some links to help:


07-29-2005, 08:45 AM
Thank You Very Much For The Advice I Will Rebuilt My 3.8 Motor As The Only Thing Wrong With It Is The High Miles And Very Little Smoke.
Now Are There Any Specific Rules I Should Follow. Like Oversize, Piston Type, Cam Size And Roller Lifters Or Not, Ect.
I Never Have Time To Go To The Track But I Am Pretty Shore I Race More Than Does That Do Go To The Track .
I Will Drive This Car Every Day. And I Donít Have A Million Dollar Budget. I Donít Want To Start With The Bolt Ons To The Have To Take Them Of And Then Rebuilt The Block And Heads .
I Want A Strong Solid Foundation Now So That When I Have The Money For The 1500.00 Turbo And The 1000.00 Intercooler I Wont Have To Do Anything Else. So If There Is A Rule Of Thumb Or List Of Them What Is It Or Where Can I Find Them. Thank You Very Much For Your Time And Very Valuable Advice. Dave.

07-29-2005, 09:51 AM
Here's some typical build ups:


Basic rebuild guide:


My two cents:

Don't overbore unless you have to due to cylinder taper or wear
Forged pistons are a good investment ... JE, Wiesco, Diamond, BRC all are good choices
Pay special attention to clearances ... for a street motor you want to be in the middle of the factory specs, IMHO
Don't go "cam crazy" for a street car ... usually something in the 208 range is big enough
Stock style replacement timing chains work very well unless this is a higher winding combination
Turbos are usually around $750 (and pretty easy to resell) ... just be sure to match converter, turbo, injector combo
Use an engine machine shop that knows Buicks if possible