Opinion/Advice building 350 SBC for kroozn on straight GAS

[xx34]

hi .. i am strongly thinking of building a SBC to run straight gas or injected gas... intentions to have it built once with it being balanced ,correct compression ratio,correct cam ,''baby mild''.,heads that work.. iron or alloys..ETC .... i try to do homework but get lots of negative advice,, gas is for BBQ'z,,petrol is more bang for your buck,, lesser new servos installing gas pumps,,price of gas is going up ,,,my car was on dual fuel and i pissed off the gas coz of cost,,,all that shit plus more which is fine.... maybe i dont see the light... well i dont understand when a friend drove his 34 to Bright and used 47 lts of GAS which is about 3hr drive $36 and a350 chev new crate engine dual fuel...and on petrol would of cost around $50 -$60.... therefore im thinking if i get an engine built CORRECTLY gas should be a good thing.... what do you guys think and can i be pointed in a good direction..thanks ..melbourne

[Twin Spinner]

Straight gas was the way to go when I had my F100 converted in 2003 but I have to be very very careful now if doing a country trip.

[FRANK BASILE]

Three things spring up for optimum. Camshaft specific for LPG operation . [Crow Cams] Ignition advance re curving and the inlet manifold open chamber design if my memory serves me well from "LPG use days". Straight gas also. Dual fuel set ups on non computer managed engine systems require compromise with ignition settings . Hardened valve seats was always the suggestion, today I would say all rebuilt or crate engines are now done as normal. Any post 74 350 will have this as factory to cope with ULP. If any of this helps. The sting now is the diminishing number of outlets supplying LPG and the closing price gap to petrol. It was once under a third, now it is a half and sometimes over a half. LPG consumption is a tad higher than petrol . May very well be worth looking at fitting an aftermarket fuel injection system. We had Commodores along the way in the family fleet all on straight gas. 4 cyl converted to 186. ,202,s ,253,308 . Yet a later injected 3.8 V6 running on basic ULP became cheaper to run.

[32coupe]

I'm still runnign LPG, and have no intention of changing any time soon.
I am still able to get it anywhere I go, and I travel from Canberra to Albury on less than $60.
As far as a built engine for Gas, I would go for alloy heads, they have stainless guides as standard, and are relativly cost efective now.
A mild cam, around 10.5 to 1 compression and a single plane manifold.
Get an Impco 425 on a Holley base, job done.Get your dizzy graphed for gas.
Happy cruising.

Cheers
Andrew

[rx4ord]

Andrew the positive news gas man.
Love to hear your ideas and views and know that you
are using gas and not panicking like some.

Tassie Dave

[turns]

I think you really have to go straight gas to get the most benefit. I had an old Holden with a Chev on duel fuel and loved it but if I had my time again with that car I would have gone straight LPG.

32 Coupe knows his stuff and has listed great advice.

Remember that you have to get your annual registration inspection (pink slip) done by an LPG certified fella (in NSW anyway). Also remember that the gas tank has to be inspected and re-stamped every 10 years. I would also suggest that you don't cut corners setting up your cooling system either.

Let us know how you go

Cheers Turns

[snowcone]

Have had dual fuel cars in the past but I have to question whether you will ever break even on this one.
For starters you are intending to spend a lot more, maybe even thousands, on building this motor for gas specs rather than just a healthy standard 350.
Then you have the initial outlay of the gas equipment and I am not sure but the rebates are probably not applicable now, so there is more cash outlayed over just a normal fuel tank and ancilliaries etc.
You will have the inconvenience of having to plan all your trips to ensure gas is available where you are going.
And then you will only "save money" if you drive it like a taxi because if you aren't doing big kms then your breakeven point on petrol cost versus gas cost is extended out over many years.
I think you have already made up your mind that you are going to do the gas thing, but I am not sure it is the same economical thing that it was 20 years ago

[Oldcol]

....yep,I reckon Snowcone has made the important points, that breakeven point on the cost of the conversion alone (not taking into account any engine stuff)....is only achieved with high mileage. Doing the run season as most blokes only seem to do now will take you a lifetime to run up the miles,if ever. And you have to consider that many of the major fuel companies have started to remove LPG pumps when they modernise their sites. Interstate is already far worse than Vic,you need to plan ahead to know where you can get it,and hope they haven't run out when you get there. A few years ago we got stuck at Gundagai when both the servo's ran out. Also had the same thing at Lithgow, and at Stawell in Vic. That really gives you the shits big time. If I was going to build another gas car ( I have 3 on gas now)....it would have to be dual fuel just for the peace of mind. One of my Pickups is on dual and it's the only one I'll take interstate.
Gas is still beaut stuff, but the economics are an issue as is the fuel companies removal of their support of the industry....for which I reckon we can blame Johnny the Bastard (Howard) who trashed the industry almost overnight when he introduced the tarrifs, which increase yearly I believe.

[xx34]

hi guys thanks for your time and input... i intend to drive it alot and go interstate,, so good chance mite go petrol,, but still in the back of my mind...thanks all much appreciated.....p.s.hope to have car on road late next year

[32V8]

If you do on gas I have a brand new Impco 425, Holley base, single plane manifold and complete ignition system to suit a small block Chev.
I was going to go gas on my pickup but did not want to mount the tank inside the rear bed, so all this stuff is gathering dust in my shed.
PM me if interested.

[T1916]

I had a mate with 2 dedicated gas falcon Utes, he got rid of them because most of the servos were no longer stocking gas. And another mate with a dual fuel Range Rover who has trouble getting gas in his travels. Most of the taxi.s have gone make away from gas to hybrids after the excise went up on gas.

Cheers GT.

[FRANK BASILE]

Might be worth looking at an aftermarket fuel injection set up. I understand these are available in the US.

[Oldcol]

I think the writing is on the wall for gas , it doesn't make a whole lot of sense to build a dedicated LPG engine at this point in time. I reckon if you (Alex) really want to to go ahead with it,build it as dual fuel. Now I know you'll have all the experts telling what a shit idea this is, but at least you won't get caught out if it all goes away ( and I think it will unfortunately). Build your engine just like you would for petrol and add a gas mixer to it. I've done the comparisons first hand and it generally makes f-all difference. Had a client who had Gas added to her secondhand Commode years ago , just on the existing engine as it was with nothing done to it at all....and it went over 200,000 miles. Only thing that stopped(or slowed it) was it started to run on 5 cyl's and we figured it'd fried some valves. So we had it in to fit a rebuilt engine to it but before we sent to oldie back,I ripped the head off just to see what it looked like after all those miles with it's original valves,etc....well, it looked pretty darn good actually. Nothing really wrong with it at all except the missing was down to a cam lobe worn down....if it wasn't for that,it'd probably still be boogeyin' along. And then there's the FB Ute with a used 186 in it we converted for another client,went just as well on Gas or Petrol, f-all difference except it ran better in the mornings on Gas than Petrol,it's still going strong maybe 15 years later.
As well as that,one on my pickup's is running a 350 that is set up for dual fuel, you could flick it from Gas to Petrol or vice versa and it'll run pretty much as strong on each. It also is a "not built for Gas engine" and I've probably put 90'000 miles on it pulling caravans,trailers,etc as well as being used every day...still goes great.
My personal take on all this is, there's a lot of mis-information around, much of it circulated by people who perhaps haven't tried stuff for themselves. Just do it...

[monte]

Since the Cabs in town have all gone to those hybred toyotoes things it is very hard to buy gas here ,I think maybe 1 servo has it and if you go up the coast you will not get far as you will run out looking for the next stop selling it .My old mate on here Dion had a gas BA Falcon and towing a van was getting 300kms out of a tank ,would be a bloody slow trip around Australia

[32coupe]

I had an old HZ statesman with a 308 in it, I did well over 200,000ks in this on LPG, no stainless valve guides.
I loved my statesman so much when it died, not the motor just the car, I transplanted the 308 into the next one.
I did have to do the bearinigs and rings, but when I had the heads checked the guy at the machine shop told me I was waisting his time.
Just goes to prove you don't need a built a gas motor to enjoy hassel free driving.

Cheers
Andrew