1994 - Engine Swap or Rebuild

[Fortran]

Greetings:

I purchased a 1994 truck recently. It currently has the 4.3 in it, but also included a 350. Here is the situation:

The man I purchased it from said it needed the passenger head gasket replaced. When I made the purchase, I did not have a definite plan as to whether to repair the 4.3 or swap in in the 350. I had it towed to an acquaintance who does auto work, and am struggling to get satisfactory answers. To my understanding, if the head gasket is bad, you should (a) replace both sides, and (b) get both of the heads themselves resurfaced. Nothing more. Repairing any cracks or warps in the heads is a different process, that may not be possible in all cases (the head is damaged beyond repair), and is not necessary if just the gaskets are bad. I never once got a clear response as to what is wrong, essentially, the only reply has been "take it to the machine shop, spend 100 bucks, and then see if the block is cracked".

First, I am a bit unclear as to what is wrong (are just the gaskets bad, is the head likely cracked, warped, etc)? I have asked, but never received a clear answer. Based on the price of 100 dollars, what would one expect - would this both resurface it (for the gaskets) AND repair and discover any cracks, or not? Next, because I am a bit afraid I will end up paying this 100 bucks only to discover they are damaged beyond repair, I am considering buying a re-manufactured head. if only one head is cracked, do I automatically need to replace both or not? Additionally, is there not a way to check if the block itself is cracked before spending hundreds of dollars on heads?

My other option is to swap in the 350. The question is, how easy is this? I specifically asked the man I bought it from, and he said that only change needed was where the motor mount bolt to the frame; all that was require wasremoving the V6, and dropping in the V8 wires and everything. However, the man I have working on the car (and another mechanic) said it is quite difficult. Which is more accurate and what approach (repairing the V6 vs swapping in the V8) would be a better idea?

Thanks and sorry for the lengthy post.

[j cAT]

its a 1994 truck so when the head is removed it will be quite clear if the head is cracked or just the head gasket.

the heads on these are cast iron so this should not be distorted.

on new engines heads are ALUM this then is a distorting material . cast iron cracks and these can be seen by an experienced engine repairer.

head gaskets usually fail when the coolant system is not properly maintained . small leaks [no pressure] T stats sticking , old corroding coolant using tap drinking water with the antifreeze.

have the head gasket replaced if the head has no cracks then do a coolant pressure test replace the coolant and T stat . use distilled water with antifreeze.

if the engine oil has coolant in it then you may want to put the 350 engine in it.

coolant will eat at the lower crankshaft bearings .

[Blue Bowtie]

There would be a bit more work involved in exchanging engines. The PCM and wire harness are likely for the 6-injector CPFI. Even if it is a TBI, the PCM would need to be reflashed not only for the injector pulses and timing curves, but the shift points.

The next question is the transmission. Many of the V-6 transmissions used a 6-plate stack in the 3-4 (direct) clutch and a thicker spacer, whereas the V-8 units would have had a full compliment of 7 disc/steel stacks.

Overall, there would be a little more homework involved, but it could be worth the extra effort.