91 5.0l ho questions urgent!

[at_the_junkyard]

I am pretty sure the timing gears are different on the 91 because of no fuel pump so you will probably have to swap the cover and timing set...basically all the parts off your 84. It can't be much different than my 80...it should all fit nicely for you. This would also be the time to install a new timing set or chain if your 84 stuff is worn at all etc.

The advantage with the 91 shortblock is it has the roller block and roller lifters already and you don't have to buy the expensive linkbar lifters to convert like I did.

I am using the stock mechanical pump on my 80 after my HO cam and head swap and don't have any issues. They are relatively cheap and you can get one at NAPA easy enough. If the pump looks questionable after 30+ years IMO maybe just get a new one while your doing it.

Cheers

[at_the_junkyard]

One other thing that you may want to also pay attention to is the length of the cam dowel that drives the timing gear.

I can't remember now but there is a longer and a shorter one and I believe you need the short one with the pump eccentric so it can bolt down properly. You should be able to pull the old one out of your 84 cam to use when your swapping etc.

[Lowetlx]

84 should have a 2 peice eccentric. That uses the short dowel. He can use the 91 chain as long as it’s not too worn. The 91 roller cam will already have the short dowel. The longer one is for one peice eccentrics

[Sask84gt]

Thanks!