big block conversion ????????????

[tbear99]

This question is how i found this site.I have an 88 blazer love the blazer but while i was otr driver the body roted from sitting.I bought a military 85 blazer with bad motor and basically a parts truck with a good body and frame interior already stripped out which is actually better for me being i want to use my interior and wiring harness from 88.The plan is lift body off and and basically build from frame up.well my little 350 while pushing decent ponies I was thinking of putting a big block in it.I can get a 91 454 SS pickup with about 140k for about 600 in spring.I was thinking i could leave tbi unit to help with fuel economy.What are some of the problems i might run into with the 454?? my dream would be to have a 427 or 396 but thinking i won't find one of them reasonable enough for me to afford.

[babyJay]

Subscribing to this thread, sounds like a cool plan. As long as you keep the 88 harness with the tbi, ecu, sensors, etc transferred to the bbc you should be good. Someone will undoubtedly correct me if Im wrong tho.

[72 CustomCamper]

The 454 is only 20 more horses than the 350 stock for stock. The torque though 85 more lbft than the 350...


Chuck

[tbear99]

baby jay thanx i was thinking same thing as keeping the wiring harness would work 72 i wasn't totally sure how much of a gain the bb would be.by the way here is a couple current pics of the 88

[babyJay]

Well, get it in there already!

[tbear99]

spring time is when i get the 454 that pic is my donor vehicle i'm taking everything from this to the military.Right now trying to learn and make sure everything will work as i think or find out if people have had problems doing similar project

[tvblazer78]

Not to bad for a parts truck. Keep us posted on this one!

[tbear99]

i've had this truck since my bro died in 96 sorta hard to stop this one but when all converted the the military 85 it will live again at least in my head

[tvblazer78]

Originally Posted by tbear99

i've had this truck since my bro died in 96 sorta hard to stop this one but when all converted the the military 85 it will live again at least in my head

Sorry about that, but happy that you are doing something with it and just not letting it rot..

[rigon4]

tbear99 did you have this for sale on craigslist a couple months ago? and were in upstate NY you from??

[tbear99]

nope never been for sale their is one that looks about identical but in really nice shape in rush.Don't know if he is selling it.that was a texas truck i believe 6 inch lift.I'm half way between rochester and syracuse right on the lake ontario

[rigon4]

there was a person sell a blazer and a body of a military one.

Fair Haven?

[tbear99]

nope never seen that one

[rigon4]

the person put it back up the other day not the same by far!!

http://syracuse.craigslist.org/cto/1226994190.html

[rigon4]

and for your swap i think the 454ss trucks are only 220 hp?? so if you got some work done to your small block you mite be going backwards

[72 CustomCamper]

230 hp @ 3600 rpm's 385 lbft torque @ 1600 rpm's...


Chuck

[79blazer]

The 454 TBI flows 650 CFM.

There is a carburetor sizing formula out there, that is a rough guide to getting the right carb air flow CFM (cubic feet per min) but It works okay for TBI.

CFM = (RPM times CID) / 3456

3600 X 454 / 3456 = 473 CFM

Though the TBI is rated 650 CFM, the motor is likely running 75% volumetric efficiency with a restrictive intake cam and exaust... 650/0.75 = 487.5 Which explains why the power peaks at 3600, because that's where the airflow peaks. This low end power is excellent for tow/hauling.

The rest of the motor (camshaft and heads,) is designed to accomidate this, so if you use a bigger TBI, not much will happen. Until you get into cams and heads. Plus the more modifications you do, the more you need to do custom chip tuning.

Basically I'd find a cheaper 454, or cheaper small block.

[tbear99]

thank you guys for the technical info.Now i'm wondering wether to find an older big block or just put money in my motor/I like the ideal of the torque of the bb

[rigon4]

sb to bb its crazy were the power is i have had couple built sb but the truck i have now has a off road 502 in it the 450 hp one and its so fun