Need Help With Blazer Engine Recommendation

blandq · November 6, 2008

Hi All;

A good friend of mine has an '89 350/290HP stock K-5 Blazer. He has recently gotten the itch to get substantially improved acceleration out of it and is looking at crate motors. He is beginning to focus on 350/383 stroked, TBI in the range of 350+HP/400+ft.lbs.

I have a good idea what he's looking for and primarily it's a seat in the pants feel when he puts his foot in it from a dead stop. He has little to no interest in going past the 85/90 speedo rating. I'm a pony car guy with a 2500 lb. car and 441 dynoed ponies with a trans and rear-end to match....I'm not the guy that understands the benefits/limitations of his tranny 700R4 W/OD?, stall converter considerations, shift-kit options, etc. that when combined with 400+ ft.lbs will give him the acceleration he's looking for.

Specing the engine is pretty straight forward, he's willing to put $5000 into a crate motor, but I'm not confident it will get the results he's looking for if we do not balance within the complete drive train. In addition, he does tow on occasion as well as 4-wheel. Nothing extreme, a nice bike trailer/Harley for towing, and muddy fields (not mudding, just getting across it.)

Any recommendations or representative trucks out there for him?

-Q

66nova · November 6, 2008

This is tough. Because we do not know what type of performance he is looking for. The combo I would like is not necessarily the combo that will make him happy or may be way too much. A stout motor making 400+lb/ft of torque will move that Blazer nicely and could have really good manors while sounding great. But you are right! The rest of the combo will have to match.

With that heavy beast, a 700r4 is not going to hold up very long with him liking to accelerate hard. They do not stand power very well. A GOOD tranny guy can build one to hold up, but I don't care what you do to them, it is NOT going to be as strong as a good old TH400. I'm not saying to go change to a TH400, but it really goes back to what he wants out of his truck and how/where he drives it. Then it also boils down to money.

Stall, you can't really decide on that until the motor/cam/heads has been decided. Too many variables right now.

Gears are another consideration here. What gears does he have and is he willing to change them if needed?

I personally would ditch the TBI if he wants to make real power. I would either go carb or upgrade the fuel inj to something like an edelbrock unit or a GM ramjet set up. What crate motor has he found that is a TBI built motor that is making over 400lb/ft.

Also, is that a crate motor that he has in his Blazer now? I certainly could be wrong, but I wasn't aware that in 89 the 350 made 290hp. If it is the original motor, and if it was originally 290hp, I am certain it does not have 290 hp now. The only reason I mention this is, if he is trying to decide how much power he wants based on how much he thinks he has now, it may not be a fair comparison. A motor that TRULY is making 350+ hp and 400+ ft/lbs can light up the seat of your pants.

More info please and we will be glad to give out knowledge/opinions/experience. Sounds like a fun build.