heater install?

[ben(riverside)]

i installed a heater in my supra saltare it has a big block 454.
my first set-up was taking water from the side drain plugs located down at the engine> into heater and T returned into the BYPASS(the small 90*angeled rubber underneath the thermostat housing).
I was under the impression that the waterflow wasn,t enough to give good heat.
So today i tapped the BYPASS.go out under the thermostat>into heater>back in watercirculation pump.
Good heat...but the thermostat now opens and close very often...heat goes up to 180-190 thermostat opens and cools down to 130...never seen it before.
It feels like there is to much resistance on the waterflow thru the heatercore.
Another option would be (replace bypass)
T the heat sending unit >heater>back to watercirculationpump.
in that case i need to remove a plug in the waterpump..the plug broke off because it is so tight.need to drill it out.

well that,s it...don,t know what to do to be safe.I don,t want to operate the engine too hot.

[01sunsportboarder]

do you not have another plug on top of the engine instead of the tstat one. you need to take water off the waterjacket after the tstat (so its hot water) (as you know) and return it just after the raw water pump with a tee fitting. at least thats what I did and it works great. rk

[Catdog2]

Can you guys provide more information about the heater type and the mounting location?

[87 Sunsport]

I bought mine through DIM, that way you can use both the Heatercraft and Discount Inboard Marine resources to troubleshoot.