LS6 vs BBK intake
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From: Howell & Fenton MI
LS6 vs BBK intake Ok guys I have a opportunity to do a straight up trade here...my LS6 intake and ported TB for a BBK with 85mm TB. So the question is...should I do it? I've read all the comparisons and not sure what to make of it. Never really considered this intake before, but since it's a straight up trade I though I might entertain the idea. Thanks
I wouldn't. It's work for very little possible gain.
If I were you, I would instead try to sell the ls6 for as much as possible and pick up one of the deals on Fast 78s in the classifieds here. I've seen several of them lately....that would better compliment your stroker motor. Honestly for your setup I would think the Fast 90/92 would be worth getting.
If I were you, I would instead try to sell the ls6 for as much as possible and pick up one of the deals on Fast 78s in the classifieds here. I've seen several of them lately....that would better compliment your stroker motor. Honestly for your setup I would think the Fast 90/92 would be worth getting.
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Ok I see. So if I was to get a Fast 78 what size TB works best, and what is a reasonable price for one in your opinion? Ideally I'd like a 92 or 102 but I'm not really in a position at the moment to spend much at all. I'm thinking I could get around $400 for my setup, and imagine a 78 Fast not costing much more no?
I've seen several of them for around $450-500 in there. You can use your stock fuel rails, stock ported TB, and everything else.
If you wanted to get really industrious you could get an 85mm TB and open up the throat of the Fast to match. Keep in mind that will take it past the sealing o-ring gasket between it and the TB so you would need to make a gasket from gasket material cut to fit or RTV.
The appeal of the Fast 78 is the slightly lower price and no extra cost for throttle bodies and it will end up within a few HP of a Fast 90 (at least on a 346ci engine). The power is in the runners and plenum volume...not the throttle body size.
If you wanted to get really industrious you could get an 85mm TB and open up the throat of the Fast to match. Keep in mind that will take it past the sealing o-ring gasket between it and the TB so you would need to make a gasket from gasket material cut to fit or RTV.
The appeal of the Fast 78 is the slightly lower price and no extra cost for throttle bodies and it will end up within a few HP of a Fast 90 (at least on a 346ci engine). The power is in the runners and plenum volume...not the throttle body size.
get a Fast 92...there is one for sale in the classifieds for 650.00. You have a 370 not a 346, it will easily offer a decent gain over the 78. Everything I have seen over the years shows a minimal difference between the LS6, bbk 85, and Fast 78 . A Fast 92 unported is only worth 10-15 over the LS6. Probably 15-20 on your 370 though. Get it ported and you might see 25+
Last edited by kinglt-1; Dec 11, 2014 at 10:14 AM.
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From: Howell & Fenton MI
Gotcha, but the stock LS1 TB is a direct match to the 78 Fast? No adapting, spacers, etc, etc..
King, I'd love a 92 ideally but simply don't have it in the budget when you factor in the TB as well
King, I'd love a 92 ideally but simply don't have it in the budget when you factor in the TB as well
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They are easy to do basic porting to with nothing but a dremel with a sanding roll on it. Keep the speed down so it cuts rather than melts and past that just take your time and don't get carried away.
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From: Howell & Fenton MI
Ok tell me what you think of this idea...sell the LS6 (but keep the TB) then buy a Fast 78...maybe port it or maybe not...then when money permits throw a 90mm shell on it with a matching TB. How does that idea sound for someone who is financially strapped now, but wants to pull the trigger on something? 
that's a solid plan IMO
get the most from your ls6 while they're high in case that Dorman intake causes a price drop on the used market, get an upgrade for cheap, and either upgrade the fast or replace it with a bigger fast later on
even unported I bet your combo picks up enough with the Fast to be worthwhile
get the most from your ls6 while they're high in case that Dorman intake causes a price drop on the used market, get an upgrade for cheap, and either upgrade the fast or replace it with a bigger fast later on
even unported I bet your combo picks up enough with the Fast to be worthwhile
This is probably the 8th time I've shared this info regarding the FAST 78....
8-11 HP over stock....Ive done the test more than once and the results have always been similar.
I originally had a ported 78 FAST on my original 346 combo with the AFR 205's and our 224/228 cam.....when I made the move to the 90 mm version I only picked up about 5-6 HP....keep in mind my stock 78 TB was also heavily reworked. Considering what I routinely see guys picking up with my ported 90 set-ups I would have to guess my ported 78 FAST with a ported 78 stock TB was worth pretty close to 20 RWHP over a stock LS6/stock 78 TB.
The FAST 78 is a solid performer but obviously the 90 unit will be a little stronger all things being equal. If you can find one for a good price don't hesitate IMO....
Tony M.
8-11 HP over stock....Ive done the test more than once and the results have always been similar.
I originally had a ported 78 FAST on my original 346 combo with the AFR 205's and our 224/228 cam.....when I made the move to the 90 mm version I only picked up about 5-6 HP....keep in mind my stock 78 TB was also heavily reworked. Considering what I routinely see guys picking up with my ported 90 set-ups I would have to guess my ported 78 FAST with a ported 78 stock TB was worth pretty close to 20 RWHP over a stock LS6/stock 78 TB.
The FAST 78 is a solid performer but obviously the 90 unit will be a little stronger all things being equal. If you can find one for a good price don't hesitate IMO....
Tony M.
Not unlike this fellow:
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From: Howell & Fenton MI
I trust Tony Mamo's experience. And again considering the 78 shares the same runner design as a 90, it makes complete sense that it will make more power up until the point the tb becomes the restriction, which the OP would probably be at, but he would still see gains.
Not unlike this fellow:
Not unlike this fellow:
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Just talked to Tony actually. He charges around $550 for porting. He says a ported 78 will get about 15-18 hp, a ported 92 about another 5-7 hp over that, and a ported 102 about another 7 hp over that
