V8 Guys, Quick Q?

[sn0border88]

So, you put the 302/351 in. Carbed or fuelie? What would you pick if you could do it again? If you did a carb, how does it do?

Eventually I want to get a 351 or 302/c6/np205 combo goin with a possibility of going to propane if its carbed.

 

[james t]

Okay, some general thoughts-

1- If you decide to go propane, and dont mind the limited fuel availability, you will LOVE it. I had a setup gathered up, but i sold it before i had a chance to run it. Sureshot40sw ran it on his old YJ, and its unbelievable how smooth it runs on BBQ gas. The motor starts up on what seems to be half of a revolution and it will idle smoother than ever.

2- Go EFI if you can, but honestly if it were a trail only rig id go propane simply because its 100x easier to swap and parts are really cheap (eBay).

3- If you decide to go carb, there really are only two easy options. Either a Motorcraft 2 barrel or a Qjet (preferably turned around backwards). I have wheeled a carb, and wheeled with alot of guys with carbs and time and time again these are the only two carbs ive seen work in every situation without stumbling. Both of these carbs flat out work offroad, and i know alot of guys running Qjets who have decided not to bother swapping to EFI because the Qjet will run on its side, on its nose, and damn near on its lid. Its the same thing with the stocker Motorcraft.

4- You will hate the gearing of the C6/205 combo and will want a doubler after your first trip. Unless you're planning on rockwells.

5- The 205 is friggin' huge, and hangs down low. Im cutting a hole in the floor of my Bronco and pushing it up through it to get decent belly clearance. Just something to think about.

 

[justin146]

You can just about go EFI for the price of a good carm. I see Mustang manifolds with most of the components on eBay all of the time. Then you'll need either a stock computer, or something aftermarket like Megasquirt. If it is a 351, look for the manifold from an F150.

 

[sn0border88]

Im almost set on propane, I dont want to deal with all the electronics and bull with the efi setups and I want to get as much crap out from under the hood as possible to fit more toys.

Reason I asked is because I was assuming it would be loads easier to go propane with carbed than EFI, or do I have this backwards?

And I guess I forgot to mention it wouldnt just be the 205, it would either get twins and gears or a 203/205 doubler but thats alot of space.

 

[Kinserin]

5- The 205 is friggin' huge, and hangs down low. Im cutting a hole in the floor of my Bronco and pushing it up through it to get decent belly clearance. Just something to think about.

Are you sure you arent talking about a 203? 205s are tiny. Although, I guess I've never actually *seen* a 205 under a truck.. Just in my backyard waiting for my 302 swap. Im hopin for a 203/205 doubler.. But Im not sure heh

I'm also looking into a propane conversion setup for my EFI 302 I've got, one of the guys I work with used to do the conversions for a shop he used to work for. If I find anything I'll send a PM your way Sno, unless you finish before I start.. haha

 

[JDraper]

I take it you're planning on making it a full time off road vehicle...

 

[sn0border88]

I have made it a full time offroad vehicle.

Welcome to 5 months ago

If anyone has more info regarding propane swaps on a 302/351 id be intrested in seeing it.

Id like to do a 351 as im hoping with the propane I can run a smaller radiator, plus im considering getting rid of the hvac stuff as well so I should have plenty of room.

 

[Mud Bug 94]

it seems to be a good choice to run the propane...insted of a c6, put in the np435...its got granny gearing and is fairly sort...

 

[wolfnutts]

i saw them do a trk on horse power tv other day on propane what kinda mileage can u get on the street ??

 

[james t]

Are you sure you arent talking about a 203? 205s are tiny. Although, I guess I've never actually *seen* a 205 under a truck.. Just in my backyard waiting for my 302 swap.

I have one in my 74 Bronco, and its up against the framerail on the driver's side. It also hangs down alot lower than the D20 it replaced. Its about twice the size of a D20. The 203 is even bigger, but that doesnt really matter since its only use to "us" is the range box... its pretty worthless in stock form. The 203 is a few inches longer than a 205, but they are both about the same width and height. Im sure the 205 can be made to fit fine in an Explorer, im just letting him know he might have to get creative getting it tucked up in there.

 

[sn0border88]

I dont feel like having a manual on the trails or I would. An auto is for me. If I go 302 route I may still try a c4/d20 combo if it looks like space for the 203/205 is tight but id rather have the doubler.

 

[james t]

You can do a C4/203/D20 doubler.

With that said, i would stick with the C6/203/205 if it were mine.

 

[sn0border88]

ya, if I did the c4/20 it would be to keep it small, the c4/203/d20 kinda defeats that. But thats an intresting combo for sure, did the c4 ever come with a 203 stock?

 

[james t]

Nope, not that i know of.

 

[minelson17]

Okay, some general thoughts-

"Either a Motorcraft 2 barrel or a Qjet (preferably turned around backwards). I have wheeled a carb, and wheeled with alot of guys with carbs and time and time again these are the only two carbs ive seen work in every situation without stumbling. Both of these carbs flat out work offroad,"

I know this is an older post, but James T, I'm looking to put a Holley 670 CFM 4 Barrel Truck Avenger on my upcoming 302 swap. Have you heard or seen the performance of these Carbs? I have "heard" they perform very well and you won't skip a beat when off roading. Any other brands you've seen fail that are supposedly "offroad"?

 

[james t]

Ive heard they work but i dont personally know anyone that runs one.

 

[minelson17]

Well, when I put one on I'll let ya know how it works!

 

[rookieshooter]

Ive heard they work but i don't personally know anyone that runs one.

You do to :
Mine is the Truck Avenger Off road carb and will climb up untill the angle is too great for the traction and does not miss a beat. Now mine is the 470, which is good up to the 302 and a bit more. I picked the smaller cfm for greater throttle responce and less bogg IMO. Now this is coupled with Edelbrock performer heads and L&L headers.
At first Holley had a porosity problem with the castings and was a real pain. But Holley gave me a free carb and I have never looked back.

Holley has a video with a rock crawler standing on it's bumper and working fine.

 

[minelson17]

You do to :
Mine is the Truck Avenger Off road carb and will climb up untill the angle is too great for the traction and does not miss a beat. Now mine is the 470, which is good up to the 302 and a bit more. I picked the smaller cfm for greater throttle responce and less bogg IMO. Now this is coupled with Edelbrock performer heads and L&L headers.
At first Holley had a porosity problem with the castings and was a real pain. But Holley gave me a free carb and I have never looked back.

Holley has a video with a rock crawler standing on it's bumper and working fine.

Thanks for the comment, I haven't gotten a lot a positive responses to my "Carbed" idea so far. I'll be doing heads and headers as well, those Edelbrocks working out good for you?

 

[rookieshooter]

Thanks for the comment, I haven't gotten a lot a positive responses to my "Carbed" idea so far. I'll be doing heads and headers as well, those Edelbrocks working out good for you?

Yes they have the large 2.09" intakes and around 1.65" exhaust. But with the short runners for low end torque.
I also just changed to a little hotter cam a couple of weeks ago...Comp Cams High Energy cam. It has a longer duration of 268 deg. It has a noticeable idle and it's RPM is from 1500 to 5500. This is the more aggresive of the High Energy cams.
Back to the carb. It is jetted for sea level so you might want to change for your elevation.

One very important thing. If you go with the high valve springs like I got, I would use an oil that still has Zinc in it for push rod engines. In fact I'd go with it no matter if you have high valve spring pressure or not. I'm using Valvoline racing oil.
I understand that Amsoil oil is fine for push rod engines also. The problem in the friction on the cam lobes. This is not much of a problem on modern roller camed engines.