HT4100 4.1, 4.5, 4.9 Discussion, significant improvements in 94/95 4.9? in Cadillac Engine Technical Discussion; Still doing some research for the 4.9 conversion and I saw a passing mention about improvements in 94/95. The only ...
Still doing some research for the 4.9 conversion and I saw a passing mention about improvements in 94/95. The only differences I'm aware of were related to the changeover from C-body to K-body which affected things like motor mounts and exhaust setup. Were there any major improvements to the internals?
It would be easier for me to use a 91-93 since the exhaust will be setup for the C-body style (in fact the OEM headers for those years are for 4.5 and 4.9 both) but if there is some huge improvement for 94/95 then I would like to know it.
I've had a few apart. As far as I can tell, no internal changes were made at all. The motor mounts and exhaust shouldn't make a difference - I believe the bosses for the motor mount brackets are the same, as well as exhaust manifold mounting. You should be able to simply bolt on your current mount brackets and exhaust manifolds to the 4.9 block and heads.
I have heard about later 4.9's coming with a revised piston skirt to reduce cold start noise, but I've never confirmed.
There were supposed to be changes in the intake and exhaust manifolds. Some of the parts that bolt on are different. There's probably not enough difference between them to change to the newer engine unless that's all that's available to you.