Swapping a 454 on propane into the blaze

[lochenjons]

My current 350 is getting tired and i'm wanting to swap to propane. I originally wanted to swap in a 383 of 400sb but couldnt find one for the price. So I'm planning on swapping a 454 into my 77 blazer instead. What am I gonna have to do? I thought id have to change motor mounts but with a little searching i hear you dont. Exhaust is gonna have to change but no big deal. Radiator needs to be changed too? I'm trying to find a complete 454/th400/np205 or 208 setup and have found a lot of good deals under $1k.

While the engine is out, anything I should do to get more power out of the propane setup?

Thanks again guys

 

[4X4HIGH]

Is this rig still going to be registered and occassionally street driven?

 

[lochenjons]

Is this rig still going to be registered and occassionally street driven?

Yup, theres plenty of propane stations areound here btw. Is there a problem with registration and propane? I heard from somewhere in CA its fine and even exempts you from smog since it burns so much cleaner. But who knows, its CA and I could be wrong

 

[4X4HIGH]

You can do it but you'll have to pay a visit to the smog referee once your swap is all done so that you can be exempted from the smog checks. In order to pass the referee the engine needs to be the same year or newer than the vehicle. Also don't forget that you will need to have ALL the required smog equipment on the engine that it originally came with even though you will be running propane. Just because a vehicle is exempt doesn't mean you can remove any of the origianl smog devices. If you don't believe me you better make a call to your local referee station.

 

[4x4shortbed]

I used to have a chevy 4x4 with a big block in it. I sold the BBC to a buddy who just had to have it & took his 350 as part trade. It was an exact swap, mounts, tranny, even the radiator hoses. Would be the same for you, just reverse of what I did. I think in cars they had different motor mounts for BBC vs SBC, but it was to get the bigger engine to sit lower in the chassis. ANYWAY......swap away! The radiator in a BBC truck is pretty big, 4 core I think. (also used 4 core in some 3/4ton's with the small block 400ci) A trip to the local junkyard would probly land you a ton of 'em.

Later- John

 

[lochenjons]

Sweet, also currently I have 4,56 gears with 35's and am going to 38's or 39.s's. Will the extra torque of the bbc make up for the gearing wuth bigger tires? Will it have the same feel as the lower gearing and being able to idle up obstacles, or will it just be able to make it over with some gas?

 

[lochenjons]

Also I have 52's up front, so I'm gonna add another leaf up front to help with the extra weight. 1 leaf should be enough right?

 

[bowtieboy4life2000]

what is the gas mileage on propane

 

[RGV72BLAZER]

make sure you feed the BB enough fuel...a single 425 impco mixer will be marginal, at best...probably a dual mixer set up. i know a guy running dual mixers on his BBC. search here or pirate for bluevienthrobber

 

[onetonbb74]

I did the swap to 454 from 350. The upper rad hose will fit with some trimming i bought a new one cause mine said 1991 on it. The radiator shroud will not fit from a sbc, get a bbc one from the jy as the sbc one sticks out too far and comes close to the belts, id grab the radiator as well, there bigger. Motor mounts are the same. Grab the 454 with all the accessories as there different from a 350. Oh, and hedders are a tight fit, but i recommend them.