[DeTomaso] lifter noise

[boyd casey]

I have what sounds like a lifter tap. I think I have hydraulic lifters but I
have never had the valve covers off. First off is there an easy way to check
(like through the oil fill opening ) if I have hydraulic or solid lifters?
Secondly if they are hydraulic (my guess) is there a way to get rid of the
noise? I have heard of hydraulic lifters collapsing , how big a job is it to
replace a bad lifter? do you have to pull the heads? can it be done from the
top of the motor with just the valve covers off and do you have to access
the cam. If it is a big job I think it may be time to re power and go to
better heads and solid lifters etc. Any suggestions would be appreciated.
Boyd