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73-87 Chevy _ GMC Trucks => Performance => Topic started by: Swettracingc10 on February 22, 2016, 12:26:39 pm
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Debating installing a blower set up on the great running low compression big block I have removed from my 86 Suburban C20. Did a few quick searches to see if any one here has this type of set up. Didn't find much. The 454 was rebuilt for the first time going on 3years now with stock cast crank, stock rods and new hypereutectic .030 pistons. Swapped the peanut heads for large oval 118cc 781casting heads with larger valves. Compression is somewhere around 8.1 because of hopes of adding a blower one day. Well that day has come. Now I'm very undecided about which brand and size trying not to make a high dollar mistake. I've heard 6-71s work well on the street. Will my bottom end take well to the added induction? What carbs to run? Not looking for dyno numbers. Just wanting something fun to drive. The other option is rebuild the engine again and bore and stroke to a 496 with more compression. I've never owned a blower set up and still fascinated by the idea. Engine is going in a 86 C10 Silverado swb fleet side pick up. Trans is a 3l80hd and rear end is a 12bolt posi with 3.73 gear. Intended use is a lot of highway riding and mostly street use. Any info or suggestions will be greatly appreciated.
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If you just want the looks, and mild performance, then a 6/71 with low boost would be ok. If it's about big performance I would go with a procharger and build the engine. For big performance with the classic roots type blower, then I would say go with a larger roots type, 8/71, 10/71 or similar. I would call BDS and get a recommendation for sizing and build suggestions.
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BDS said 8-71 as well. Keep it around 3-5psi and I should be ok with stock internals. Looks like I made a mistake by cheaping out on the pistons. A non intercooled pro charger may be the way to go at this point and an engine rebuild seems to be highly recommend. Back to the drawing board as I need to do more research. No point in spending $4k on induction that has to be limited. SomeTexan your input is greatly appreciated.
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You can underdrive a bigger blower until you can build the engine. Just don't push it very hard until you upgrade to a forged crank with 2 keyways. That's a lot of mass to spin off of a cast crank with a single key holding the damper in place.
I will say, I do love turbo's for something like this. They aren't being turned by the crank, and it's easier to limit boost with a bov and a wastegate. Of course, a pro-built blow through carb isn't cheap, or efi swap for that matter.
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Wasn't even factoring in the carb or efi, good point. From a budget perspective I have a buddy suggesting a pump has 540ci build out of a cheap virgin gm 502ci block. Says it will be everything I could want in a street car. Its amazing how fast you end up back at square one.
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Suck-through carbs are cheaper than blow through. You could get a pair of predator carbs for an 8/71 for less than a single, well set up blow thru. You also have to consider fuel pumps, ignition (hei isn't going to fit behind the blower) exhaust, cooling etc. It all adds up.
A 540 would be fun as well. Build it at a moderate compression so you can add boost later if you want. Power is addictive. I haven't even got my 6.0 build done and I'm already planning on its replacement and gathering parts. Dart LSNext2 billet block, billet crank with center counterweights, LSX-DR heads... Not cheap.
Have you considered going with an 8.1 pull out? Get your efi and a bigger, higher performance big block. They will take some boost as well and have decent forged internals if it doesn't have enough power as it is. I'm sure buying one, getting the harness done and all would be cheaper than building a 540.
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And I've passed up on quite a few of those in the past. I use to find those monsters for little to nothing. I've had the impression or misconception that aftermarket products were limited so I never took real interest. I'll have to do more research on those things. I assume it would be ideal to find a whole truck for harness, ecm, radiator, accessories ect.. Like any other ls donor correct? Once again great suggestion. All ideas have been greatly appreciated.
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And I've passed up on quite a few of those in the past. I use to find those monsters for little to nothing. I've had the impression or misconception that aftermarket products were limited so I never took real interest. I'll have to do more research on those things. I assume it would be ideal to find a whole truck for harness, ecm, radiator, accessories ect.. Like any other ls donor correct? Once again great suggestion. All ideas have been greatly appreciated.
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Aftermarket parts are avalible, they are just a big block with an LS computer basically. A whole donor truck would be nice, but like an ls, you often find pull outs with all the accessories, harness and computer. Trans too. You could move over the entire cooling system, or use what you have in the truck. They come with the aluminum radiator that has plastic tanks, a design I'm not fond of. Rewiring the harness isn't hard, but can be time consuming, you can do it yourself or have a shop do it. I believe they still use standard big block mounts, so getting the engine in should be easy enough. Injectors are the same style as the Vortec ls injectors, so there are lots of options on the market for however you build it.
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6-71, or 8-71. Doesn't really matter which. Both can be made to work.
On that engine I was thinking 4psi so 3~5 agrees with my recommendation. 8)
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If it absolutely has to be a blower and not a hairdryer, then I'd have to go with pro-charger hands down. outside of the ability to make more boost than an old fashioned roots style blower it also takes les power to run and you do not have to modify your hood, keeping a more sleeper style to sneak up on unsuspecting F-words!