Engine Swap Question

[Midgetv2]

just curious but im thinking about swaping the engine i have in my truck now for either a 383 stroker or a 454 chevy bigblock. right now i have the 305 that came stock in the truck. its a 98 sierra SLE. my question is, for either of them will i have to mess with the transmission or will it just bolt up no problem.

any imput would be great, just curious for now might be a while before i can do it.

[Teamhp]

They both should bolt right up to 700r4

[Mike G]

Your 98 is running a 4L60 I believe and it will be a direct swap to the 383 (350 based motor), the 454 however, I think, has a different bolt pattern (I can be corrected, it's OK) and they were usually backed by the 4L80 trans. Either way, you will need to upgrade your PCM accordingly...

--Mike

[gregrocks89]

to my knowledge the big block wont fit but the 383 will bolt up without any issues

[rickpilgrim]

to my knowledge the big block wont fit but the 383 will bolt up without any issues

 

I would go with the 454. Here's 5 reasons-

 

1st- It will use the same mounts, has the correct bellhousing pattern and flexplate is drilled correct.

2nd- 1hp per 1cid is still streetable IE-383=383hp, 454=454hp you get the idea.

3rd- with either your PCM(computor) will not work correctly but a 454 pcm can be found in junkyard.

4th- 454 is Big Block way cool, a 383 is well, a 383.

5th- either will probably kill the stock trans, junkyard 4l80E and driveshaft/crossmember for 454 is factory for 3/4-

1ton trucks and will pretty much bolt in 1500's

 

We put a 509 Caddy in our 93 dually, pics are on www.webshots.com , user rickpilgrim take a look. http://community.webshots.com/user/rickpilgrim

[gregrocks89]

I would go with the 454. Here's 5 reasons-

 

1st- It will use the same mounts, has the correct bellhousing pattern and flexplate is drilled correct.

2nd- 1hp per 1cid is still streetable IE-383=383hp, 454=454hp you get the idea.

3rd- with either your PCM(computor) will not work correctly but a 454 pcm can be found in junkyard.

4th- 454 is Big Block way cool, a 383 is well, a 383.

5th- either will probably kill the stock trans, junkyard 4l80E and driveshaft/crossmember for 454 is factory for 3/4-

1ton trucks and will pretty much bolt in 1500's

,

We put a 509 Caddy in our 93 dually, pics are on www.webshots.com , user rickpilgrim take a look. http://community.webshots.com/user/rickpilgrim

 

 

Firstly never use the engine size to relate to horsepower. A stock 98 gmc 350 vortec is 255hp out of the factory

 

Secondly, I blew the engine in my 98 gm and putting a modded crate 350 in it as we speak. take a look at the 454 mounts and the mounts in the truck they dont match.

[rickpilgrim]

I would go with the 454. Here's 5 reasons-

 

1st- It will use the same mounts, has the correct bellhousing pattern and flexplate is drilled correct.

2nd- 1hp per 1cid is still streetable IE-383=383hp, 454=454hp you get the idea.

3rd- with either your PCM(computor) will not work correctly but a 454 pcm can be found in junkyard.

4th- 454 is Big Block way cool, a 383 is well, a 383.

5th- either will probably kill the stock trans, junkyard 4l80E and driveshaft/crossmember for 454 is factory for 3/4-

1ton trucks and will pretty much bolt in 1500's

,

We put a 509 Caddy in our 93 dually, pics are on www.webshots.com , user rickpilgrim take a look. http://community.webshots.com/user/rickpilgrim

 

 

Firstly never use the engine size to relate to horsepower. A stock 98 gmc 350 vortec is 255hp out of the factory

 

Secondly, I blew the engine in my 98 gm and putting a modded crate 350 in it as we speak. take a look at the 454 mounts and the mounts in the truck they dont match.

 

 

One- I have a nice side business building engines for folks and most agree that 1hp/ 1cu in is about the edge of streetability, which means it will start easily in our 20 degree below zero winter and perform as well as it does on a 85 degree day. It will sound mean but have good street manners at lights and in traffic, plus at any rpm you can floor it with no bog, backfire and other drama. It should go at least 70K mile with no teardown or gasket changes.

My point is you can make 600 hp with a 350 but it will require ALOT of dollars and longitivity will be very limited, and good luck firing up on a cold day, which I like in my truck.

Take a 454 and that 100 extra cubes makes it a lot less expensive and gives ALOT better street maners to make power, that's why Chevy made the Mark IV, to do what the small block couldn't do and have a warranty to go with. Modern dyno tests of factory hi po BB Chevys easily go into 5-600 hp range, sbc is a good motor but is not all that, especially in a truck. Plus in a truck the 454 will give more torque than the sbc.

And I own a 98 K3500 CC lwb with the vortec 350, 4l80e, 4.11 and the 93 dually when it was 6.5TD had 4l80e and 4.11. the 93 was 190hp and the 98 has 255hp, I can tell you with the trailer the 93 would out pull, out accelerate and had higher top speed with 65 less hp, now it has the Caddy and even my bothers Duramax has trouble ot pulling that.

As to your motor mount statement, we just put a 396 in my kids 92 Camaro, and we used the stock 305 mounts with no issues whatsoever, and we used the 350 mounts on a 402 in a 96 K2500 again there was not a problem there either. I suppose if you go way back, pre 75 or so maybe the mounts are different and I haven't seen them so you might be right, I can't say.

[rockcrusherrevived]

just curious but im thinking about swaping the engine i have in my truck now for either a 383 stroker or a 454 chevy bigblock. right now i have the 305 that came stock in the truck. its a 98 sierra SLE. my question is, for either of them will i have to mess with the transmission or will it just bolt up no problem.

any imput would be great, just curious for now might be a while before i can do it.

 

your 454 is extrenally balanced so you will need to switch your ring gear otherwise you will have a major major shake. the 383 could be internally balance depending on the crankshaft used if the crank was used from a 400 then it also is externally balanced