Agent13

iTrader: (2)

Hello everyone.

I am swapping an LS3 into my '90 C4 and need some fuel system advice.

My plan is to use the C5 filter/regulator and bend up some hard line to the motor.

I purchased this 3/8 line that I was hoping to cut in half. My plan was to use one side for the output on the filter and the other for the hose that goes from the fuel line to fuel rail and to adapt 3/8 hard line in between. The problem is that the opening is smaller than the one coming from the filter and rail.







Can this be opened up or does anyone know where to find the proper one?

The other problem is that the return line from the filter is 5/16 but the factory return to the tank on the '90 is 3/8. Does anyone know which way is the best to adapt this? I found this connector for the return line by the filter that may be of use.





Thanks for your help!

70cartruck

iTrader: (1)

i dont think the line you have will work.....if you are going to go that route you could use the factory type of hose and connectors...( i believe are dorman)...cheap but you have to use an install tool...i think?

i swapped an lq4 into a 1970 elcamino and had to decide which way to go also...was going to use the corvette c5 reg but instead just went to an lines and fittings....a little pricey but worked very well

imo...i think it would be easier for you to run an aftermarket fuel pressure reg. and figure out a way to mate everything else up.....the 3/8 return line will still work..just not with the c5 regulators 5/16 size....

ls1nova71

iTrader: (4)

You can grind a little off of that line to open it up some more, or drill it, just be sure to blow it out real good to get any metal shavings out of it. And that fitting by your fuel filter is just a 3/8 o ring to 3/8 o ring fitting, probably won't help you much. As for the 3/8 to 5/16 delima, I would get a quick connect fitting for the filter, put a piece of 5/16 fuel injection hose on it, then push the 5/16 hose on the 3/8 metal line. Do the first part of a double flare, just don't go overboard, you just need a small bead so when you clamp it, it can't pull off. It won't be easy to get on, but it will go on.

Agent13

iTrader: (2)

Thanks 70cartruck and ls1nova71.

I was thinking about this earlier today...

If I purchase Russell 640860 which is a 5/16 quick connect to -6AN for the return from the new filter and use Russell 648060 which is a male 16x1.5 mm o ring to -6AN adapter and connect it to the stock return fitting I can solve the 5/16 to 3/8 problem. I can also connect the inlet with Russell 640850 3/8 quick connect to -6AN on the filter and Russell 640830 16x 1.5mm female to -6AN on the fitting that connected to the original TPI fuel filter. Is this overkill? Would it be better to just run fuel injection hose with clamps on the inlet and return like ls1nova71 suggested?

Then I can run the 3/8 hard line from the output of the new filter to the rail and use the factory LS3 hose from the rail to the new hard line.