Originally Posted by Mr.Dunn
I have a 1995 350 5.7 TBI and I want to put it into a 1997 GMC 1500 Truck that had a Vortec engine. Will it be a compatible swap?
Not easy this is a system generation jump from OBD I to OBD II. The injection systems are different as is ignition and even the intake and heads.
A short block exchange is not too difficult and nearly interchangeable, but the top end from the heads, intake system, injection system, and ignition are very different and not even bolt position is similar as to how the TBI intake bolts to the TBI heads as how the Vortec intake bolts to Vortec heads.
You could do a short block swap, but the TBI block has a very mild flat tappet cam which might mess up the Vortec computer as it is expecting a cam with 20 some more degrees of timing compared to the TBI. The Vortec also has a roller cam, some 95 TBI blocks will accept this set up sometimes needing some finish work but the basic provisions are there. An alternative flat tappet cam would be the Edelbrock 3702 which times pretty close to the Vortec roller. The Vortecs front cover would have to be used as would the damper assembly as these have a crank position sensor system that the TBI engine doesn't.The bolt pattern has different details but is easily swapped. The Vortec coolant pump also has to come over because it plumbs differently to the ancillaries and possibly the factory built in bypass which starts to change configuration with the Vortec engine but is inconsistent as to what is there till about mid year 97. As an assembly the Vortec heads, intake, injection, and EGR which includes the exhaust manifold have to be used on the TBI block. Same for distributor.
Done this way has a lot of details to keep track of but unless you get into a flat tappet to roller cam swap there is no unusual machining requirement which that can have if the provisions aren't machined.