Mercruiser 4.3L engine replacement

[ThunderCraftProject]

Hi all,
I'm replacing the engine in my 1990 Thundercraft 1750LS and need some confirmation before I actually purchase it. Here are the specs on my existing engine: 4.3L, V6, 262CID, 175HP, and 2BBL carb (I can upload photos if needed). I plan on purchasing a long-block GM replacement from Summit Racing unless someone has another reputable/reasonable company. Here is the link: https://www.summitracing.com/search...l-262?SortBy=DisplayPrice&SortOrder=Ascending. I'm thinking about an ATK marine replacement, but the different model numbers are confusing. Can someone shed some light on the exact replacement I need? Something to do with one or two piece seals? Help!!
Thanks.

 

[Bondo]

Something to do with one or two piece seals?

Ayuh,..... Welcome Aboard,.... The rear seal thing happened in '86/ '87 for the V-motors from Chevy, the I-4s in '90,....

If ya go electric fuel pump, 'n a new intake manifold, you can jump right into the current production V-6, 4.3l with Vortec heads,....

 

[Scott Danforth]

welcome aboard.

you have a non-balance shaft motor with a 1-piece rear main. the 4.3 was only available in 1985 with the 2-pease rear main seal.

if you replace the motor with a balance shaft motor, you will need to change the motor mounts.

I would go for a custom build, non-balance shaft motor with vortec heads and intake myself.

 

[AShipShow]

Scott, what's different about the motor mounts? You have me freaked out lol.. I put a non balance shaft in my stingray that had a blown balance shaft...

Other than that I agree with Scott... I got a good long block from a s10 and swapped over my marine stuff and put on vortec heads for less than a reman long block.

 

[Scott Danforth]

Non ballance shaft motors use the squishy mounts. The balance shaft motors use same mounts as 5.0 and 5.7

 

[achris]

.... Here are the specs on my existing engine: 4.3L, V6, 262CID, 175HP, and 2BBL carb (I can upload photos if needed)....

The 4.3 litre V6 has been used in various configurations since 1985.... the 175hp 2bbl was current from 1985 to 1996

An engine serial number will clear up any confusion about balance shaft or non-balance shaft....

Chris.......

 

[ThunderCraftProject]

Thank you all for responses. The engine serial is #0C862381 and model is #443B100CS if this helps. So I'm looking for a balanced long block with vortec heads and 1-piece rear seal, which requires new engine mounts and an electric fuel pump?

 

[Rick Stephens]

welcome aboard.

you have a non-balance shaft motor with a 1-piece rear main. the 4.3 was only available in 1985 with the 2-pease rear main seal.

if you replace the motor with a balance shaft motor, you will need to change the motor mounts.

I would go for a custom build, non-balance shaft motor with vortec heads and intake myself.

Mount height is the same. If one changed to a balance shaft motor the fluid mounts would still work fine. They are just more expensive to replace.

I have a custom build non-balance shaft Vortec motor. Runs like a striped assholio ape. I left it on fluid mounts, of course.