Hey guys,

I have a 79 LTD in the midst of a resto, and am considering a straight gas conversion, and as far as i know, this will consist of replacijng the carb with a gas throttle body, and replacing all the petrol lines/tank etc with gas gear, is this correct?

Also, within the rebuild, i was hoping to put a cam in, mainly for the lumpy sound, but also to make up for the car weighing so much and being on gas. So i was wondering of all the gas v8 owners on here, do you have aftermarket cams installed, and with choosing, do you follow the same guidlines as petrol? Is it safe to have a big cam on a gas motor?

The last are probably real stupid questions, but i know little about gas, and still want to install a nice cam.

Andrew.

Crow recommend the 21771 grind and I found it really great in mine. You are going to face difficulty trying to get a really lumpy cam to work well down low with the LPG as the LPG relies on vacuum and velocity and big cams lack in the vacuum dept.

I see. I will look into the cam you quoted, I don't need to go too lumpy, as its a cruiser anyway, hoping to make up for the weight disadvantage, haha.

Do you have many other mods to the enigne? What sort of intake setup?

Thanks man.

Im in the same delema at the moment. But my engine is for a truck.
Just yesterday I was talking to a knowledgable gas guy, who said that it is just as effective to remove 1/2"-3/4" from the splitter in a duel plain manifold as it was to fit a single plain manifold as this allows the pressure to equalise between the two sides.
As far as the type of manifold the runner length dosnt affect gas as it does petrol at it is already a vapor unlike petrol which needs to vaporis.
Crow has 2 cams which would be suitable for your application.

Interesting, thanks for the info clint!

To give you a bit of an idea, Mine was a 351 clevo in a Landau which with all the other crapolla in it plus the LPG gear tipped the scales at around 2000kg. It had a 2.75:1 diff ratio and a 3sp FMX tranny. I put a 2200rpm stall converter in it, had the heads serviced and new K-Line bronze guies and hardened valve seats fitted. The valve springs were the crow units recommended for that cam and lifters were std. I used closed chamber 2V heads fitted with 4V valves, this boosted compression but the 2V runners made for better velocity and low down torque for the same reason I used the std 2V dual plane manifold. I altered the dizzy to have a total advance of no more than 15 degrees and ran 18 degrees at idle and it maxed out at 33 degrees. The 33 max avoided pinging and the 18 at idle along with the stally made for an impressive take off for an LPG vehicle. To give you an idea of its performance from a rolling start of 140km/h it would accelerate to just over 240km/h and backed off to 200 for the braking area within a space of 950 metres. Speed was limited to just over 240 which suited me because over that you ran out of gas it needed a second converter and bigger line. It was a very deceiving car as the power delivery was smooth and just kept incresing , it was only when you noticed you were leaving all behind and looked at the speedo you thought S@*t. I was in my EF XR8 one day with my mate driving my landau to get some paint done I got beside him and without warning pulled the XR back to 3rd and tramped it. He had to react first but did so quickly. There was no kick down connected on the landau so he manually pulled it back and after the initial lag from me getting the jump he not only stayed with me immediately but within seconds was screaming past me. I reckon it was awesome as do my mates and the guy I sold it to in the states and his mates reckon its a weapon too. So you can gather Yeh I think that cam is OK.

cheers
howesy@myrealbox.com

NOTE -: Make sure the cam is dialled in properly it makes all the difference. If you give the cam an extra 1 or 2 degrees advance that will bring the torque in lower. But std is fine

I fitted Crane roller rockers to top end as well

cheers
howesy@myrealbox.com

excellent, thanks for that info mate. I guess i'll shoot for a similar rebuild as yours.

What size tank is it and what milage?


Thanks guys.

because I wanted it to fit right up under the parcel shelf I opted for a small tank aroun 55litres which had around 48 litres usable gas. On that motor I used to get 200 K's out of around 45litres so in todays figes I suppose at 80 cents a litre it would cost $18 per 100 K's at 50 cents a litre around $11 per 100K's

Wow, thats pretty good then for a mild 351.

Thanks heaps mate for the info.

Hey hey,

I have revived this topic because the car in questions is about to be back on the road. I pretty much have everything bar the throttle body covered from another vehicle. Its all in good condition, and the tank is in date.

My questions is about the throttle body. Is it worth getting a second hand one, and where would i get one besides a wrecker?

And if no to secondhand, can anyone recommend/suggest a place is brisbane somewhere that i can get a good gas throttle body to suit a clevo?

Cheers lads.

Nice.

I looked at the gas research site last night, but f**k i hate internet shopping. I'm not sure exactly what i need, and the site layout is crap (to me, a non internet savvy dude).

I'm hoping to find a shop that i can just walk into and buy what i need. I'm not looking for more performance, as long as i don't lose any. I will look at the impco 425.

So the impco mixer in the system that sits on top of the carb?

Interesting. That looks like waht i'll shoot for.

Do you know what its worth/where i can get one?

I assume an air cleaner fits over the top of the mixer?

Than ks for the pic mate, and the knowledge.

Excellent.

So waht do you mean by baseplate? in your pic it looks like the whole carbi is what your refering to?

I have a 600 vac sec on it now, can i use this/part of this?

Sorry for the stupid q's, this is my first gas setup, i've always just had petrol carb.

Excellent, thats awesome.

Thanks for your input, i want to know all i can about the gas conversion before i take it on. I have been in a gas explosin before, and really wanna try and avoid it again. HAHA.

I will have a look on fleabay for a mixer.