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Topic Review (Newest First)
06-06-2012 02:38 PM
therammstein I was not the one that started this thread wanting to fab an intake, how ever that does seem to be the best solution to both the lack of any parts available and also excess weight.
As far as being properly done, I have done and will do my home work before I go all in. I have been a mechanic for 33 years and have built many hot rods and sports cars. That being said I would not be bothered if I missed out on 2% horse power because I didn't get the optimum plenum length. I care more about cool and unique.
I leave speed to my Bikes and sports cars. It already runs as strong as my buddies 72 chevy 350 and sounds cool doing it.
06-06-2012 11:27 AM
ap72 So are you still looking to fab an intake manifold? If so id tune your runner length and crosssections to give you peak power right at your cruising rpm. Id also go itb as it makes it easier to get your desired lengths with a decent package size. Properly done headers, induction, head porting, vj, and a cam may be able to double your power at cruise- which is a hell of an increase but everything needs to be properly designed.
06-06-2012 10:09 AM
therammstein That carb should be much better than stock. How does it run?

Obviously I have lofty goals for my GMC 305 but I plan on doing it in steps, like now that I have a Big (too Big for now) carb I will be fabbing up some headers and maybe even an intake manifold. Then later the Turbo.

First thing is to get some better gears in the back, she has 4.11:1 posi stock, but all of that low end torque I would like to go with more like 3.50:1.
06-05-2012 08:22 PM
REDZAW
305 v6

not sure if its an upgrade but my 305 v6 has a 2 barrel 350 cfm holley carb on it with no apparent modifications to the intake
03-04-2012 03:41 PM
therammstein there is a guy on youtube dynoing a 250 chevy l6 turbo. he is very low tech but it works well. I will try to find the link later.
03-03-2012 09:09 AM
ChevelleSS_LS6
Quote:
Originally Posted by against all odds
i love this engine series, but for general hotrodding what advantage does it have over the chevy v-6 or inline 6?

It makes you wonder why gmc went to all chevy power by 69?
Cost cutting. Why did Buick, Pontiac, and Olds get all Chevrolet engines a decade later?

Okay... I'm a bit wrong here... the Quad4 is the last "Oldsmobile" engine, and the Northstar (and its 'shortstar v6') are Cadillac, and the 3800 was a Buick design.

Currently, I think the only non-Chevy engine is the Northstar engine. Sure, Cadillac may have different heads for the direct injection on the 3.6L v6, but I'm pretty darn sure it's the same shortblock, perhaps with different pistons.

It's part of why GM killed off Olds. Olds is a luxury brand like Buick, and they were 'cannibalizing' each other. So, GM kills Olds so it can have operating costs for only one "nicer than Chevy, but not quite Cadillac" division.

As for Pontiac, they were just a sportier designed Chevrolet for the past 20 years, maybe with slightly different spring rates. But I'm sick of "cloning" cars. In a way I'm glad to see Pontiac and Olds go away after being "Chevy clones". In a way I'm sad, as at one time they were great divisions with significant differences from your average Chevrolet, differences worth (in my opinion) paying for.

As for building the GMC 302 v6, or any other 'oddball' engine for that matter, go for it! I have far more admiration for 'different' than "another sbc/LSx". I can't say I've ever seen a turbo'd straight six '69 Camaro.
03-03-2012 08:19 AM
against all odds i love this engine series, but for general hotrodding what advantage does it have over the chevy v-6 or inline 6?

It makes you wonder why gmc went to all chevy power by 69?
03-02-2012 04:24 PM
therammstein I know it's old, someone posted on it last month so it is still live.
03-02-2012 02:52 PM
DoubleVision Funny enough. This thread is 3 years old.
03-02-2012 01:59 PM
therammstein funny, I have been rounding up parts for a turbo setup for two years now. I have everything I need, but I think that I will be running EFI of some kind so that I don't have to mess with pressurizing a carb, that can be a pain.
03-02-2012 01:41 PM
Rocketile
Quote:
Originally Posted by therammstein
I have a 68 GMC with a 305 v6 that i have been working on for a while now. It bothers me that there are so many people on a hotrod sight that say "don't waste your time with that". Hot rodding is taking something that is sock and making it different or you own, not the same as everyone else has.

I have adapted a Carter 600 CFM 4v to my stock manifold, and the truck came to me with new dual 2 1/2" exhaust. my truck runs strong and will rev just fine. That cab that GMC put on at the factory is the big problem. I have been a heavy truck mechanic for over twenty five years and have never seen an engine that was designed for low RPM, they are usually limited by one component or an other, these engine just can't breath. with the new carb my engine will run 5,000 RPM all day long. I run light weight full synthetic oil in it and average 14 MPG, not the typical 7 MPG that you get with the stock set up. If my v6 were to bow I would find an other over a SB any day.
That is one problem, "they can't breathe". Judging by the fact that you can't get your thumb into the exhaust port past where the internal water jacket casting is, a great hot rodding feat would be to come up with a performance head for this thing. I have even been told by folks who have ported these that the magnum heads offer no advantage over the smaller head when all porting is said and done. I have noticed that there are several varieties of these heads which include monster size sodium filled stems that definitely choke it down. Given the exhaust port limitation in flow, a turbo charger may be the easy way out to get the HP potential.

Yes... true hot rodding ingenuity in play. Anyone can bolt aftermarket parts together but who has the fastest 305 V6 GMC??? sounds like a Bonneville challenge in the works.
03-02-2012 12:25 PM
therammstein I have a 68 GMC with a 305 v6 that i have been working on for a while now. It bothers me that there are so many people on a hotrod sight that say "don't waste your time with that". Hot rodding is taking something that is sock and making it different or you own, not the same as everyone else has.

I have adapted a Carter 600 CFM 4v to my stock manifold, and the truck came to me with new dual 2 1/2" exhaust. my truck runs strong and will rev just fine. That cab that GMC put on at the factory is the big problem. I have been a heavy truck mechanic for over twenty five years and have never seen an engine that was designed for low RPM, they are usually limited by one component or an other, these engine just can't breath. with the new carb my engine will run 5,000 RPM all day long. I run light weight full synthetic oil in it and average 14 MPG, not the typical 7 MPG that you get with the stock set up. If my v6 were to bow I would find an other over a SB any day.
01-18-2011 09:22 AM
matts37chev im kinda disappointed he couldnt get it done and had to put a sbc in it
i would have liked to see somthing cool (read different) happen there
01-18-2011 02:11 AM
crankshaft3rd
keep at it!

im new here myself but u are in the right frame of mind. just because someone hasnt done it before you does not at all mean its dumb worthless or a stupid goal. if you flip through a jegs or summit catalog every single item you see was someones "dumb idea"! im sure far enough back the candle was a "bad idea" to some one. lol just keep at it even if ther is next to no hp gain, how many other people will have what you have? and last i checked rodding was as much being unique as it was being fast and professional. do it once do it right and killem all. see you at the light.
01-18-2011 12:57 AM
68GMCWRECK
still playin' with the v6?

just wondering how is going, see been dead for while, wondering if going to get a response. af far as the 305, have on myself in a wrecker. ALWAYS starts, truck weighs 7000lb empty rolled over the scales at over 15000lb. not bad for a 3/4t chassis. rarly rev over 2500, no need....... anyway..... if still have motor(s)...... we have a bit of 305/51/79 & 401s around here.....anyway...good luck happy building.
-jon
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