need my 85 720 running right again

[nskale85720]

anyone out there that can explain or lead me in right direction of fixing my truck i recently had head gasket go on my 85 720 z24 it wasnt circulating properly and when head gasket went out engine still ran norma lexcept the overheating didnt knock or anything so i pulled old engine out and bought a replacement with low milage got everything back in and set timing but now engine struggles too start like a dead battery even though battery is brandnew when i get it started it runs smooth but now when i push gas white smoke and a little fire comes out pipe its running hot and air blowing out valve cover breather im totally confused on all of this ive read contless articals and nothing is fixing issue any help would be greatly appriciated 

[datzenmike]

Did you see this low mileage engine running?

 

Check the plug wires, it's easy to mix them up.

 

White 'smoke' sounds like steam from a blown head gasket which is common on the Z24. Maybe why it was for sale. Does the coolant push out the rad cap? are there bubbles in the coolant with the cap off and engine running? Does it constantly need coolant to be 'topped up'?

[nskale85720]

i put water in it struggles too start top radiator hose gets really stiff and hot then after running for awhile the heater hose gets scaulding hot and radiator hose goes too normal 

 

[datzenmike]

Start it up cold with the rad cap off and see if coolant gets pushed out. Does the coolant push out the rad cap? are there bubbles in the coolant with the cap off and engine running? Does it constantly need coolant to be 'topped up'? Compression might be being pushed into the cooling system making the hoses hard.