305 to 350

[sam0822]

I have a 98 gmc c1500 with a 305. Thinking about swapping in a 350. I know the two engines are very similar, so could I reuse all the accessories and exhaust? Also will it need a tune? Does the engine need to be from the same generation or could I use a later one?

 

[df2x4]

Also will it need a tune?

Yes, either that or you'll need to swap in a '98+ PCM from a 350 truck with the same transmission and gearing as yours.

 

[454cid]

I have a 98 gmc c1500 with a 305. Thinking about swapping in a 350. I know the two engines are very similar, so could I reuse all the accessories and exhaust? Also will it need a tune? Does the engine need to be from the same generation or could I use a later one?

You have the last generation of the original small block.... there is no later one. It ran until 2001 or 2002 in vans, and was the same as what would have been used in 98.

 

[L31MaxExpress]

You have the last generation of the original small block.... there is no later one. It ran until 2001 or 2002 in vans, and was the same as what would have been used in 98.

Only change post 2000 was the 2001 and 2002 blocks have metric holes for the engine mounts and bellhousings. 350 was used in production vehicles until 2007 or 2008. One of the engines I put in a 98 Tahoe came out of an 04 GMT800.

 

[L31MaxExpress]

Yes, either that or you'll need to swap in a '98+ PCM from a 350 truck with the same transmission and gearing as yours.

Will also need to change the cats and 02 sensor setup for that. 305s had 3 02 sensors before the cat, a single cat and one downstream sensor. 350 had dual cats and a sensor before and after each cat.

 

[454cid]

Only change post 2000 was the 2001 and 2002 blocks have metric holes for the engine mounts and bellhousings. 350 was used in production vehicles until 2007 or 2008. One of the engines I put in a 98 Tahoe came out of an 04 GMT800.

That sounds like your parts truck was from Mexico. I think MX market trucks used the 350 longer..... US use ended in vans when the van was redesigned based on the 800.

 

[L31MaxExpress]

That sounds like your parts truck was from Mexico. I think MX market trucks used the 350 longer..... US use ended in vans when the van was redesigned based on the 800.

It was but they are not uncommon down here in Texas.