4speed455

I’m looking to replace my transmission cooler lines in my 70 Cutlass with 455 and hooker headers. Is it possible to use factory lines with the headers, either by rerouting or messaging? Also is their any difference in the 70-72 lines? In-line has different part numbers for different models but the only stainless ones they list on eBay are for 72 with th350 or th400. Would these work on my 70 with headers? https://www.ebay.com/itm/39057051557...53.m1438.l2649

matt69olds

I wouldn’t be surprised if the 350 and 400 transmission cars use different part number cooler lines. In the real world, you can interchange them with minor bending.

With some minor bending you can get the cooler lined to fit the headers. Worst case, get a couple long pieces of 5/16 steel tubing from the parts store and bend your own. This is probably the best/cheapest option if your existing lines aren’t in the best condition.

Get the longest pieces of 5/16 lines the stores carry, you can always make them shorter.

4speed455

Thanks Matt. It seems more year specific then transmission. Some vendors list 68-72 and some list 69-71. The only stainless ones I could find were listed as only 72. My car has rubber transmission cooler lines, hose clamped to the cut off ends of the factory lines. The hose is rated for transmission fluid and I haven’t had any issues, I would just feel better with hard steel lines.

matt69olds

As long as the hose is rated for transmission fluid, and the steel lines have barbs or a flange to keep the hose from slipping off, there is nothing wrong with hose. Lots of automakers use hose from the factory.

I don’t know why there are different numbers for the lines for the different years. To the best of my knowledge, there is no dimensional changes in the transmission, core support or radiator in the 68-72 cars.

Since your installing headers, I would think any reproduction line would fit around the headers with some minor bending for clearance.

4speed455

My steel lines have no barb or flange. They just cut the ends of the factory lines and clamped hose to that. I assumed that the at least the 70-72 lines would all be the same. I was just concerned because I know the radiator design changed slightly in 72. I wasn’t sure if the location or size of the fittings on the radiator changed. Most vendors list one part number for all so I will probably just order the stainless ones listed for 72 only. If there are any fitment issues I will report back. Thanks again.

matt69olds

Rubber hose on steel lines with no flange or barb is asking for trouble. The only thing keeping the hose on the line is the friction of a hose clamp. If the line comes off, best situation is a mess under the car. Worst case, a fire.

Jeff Stout

For sure do not use the no barb or the no flange fitting. I did it on demolition derby car and it finally came off and the fire was in the motor, windshield , firewall area. Took me about 3 seconds to get out of car as it was scary

4speed455

Thanks guys, that’s what I was afraid of. I have had a tranny fluid fire in another vehicle. The tranny cooler in the radiator ruptured allowing the coolant to mix with transmission fluid. When the transmission got hot the water turned to steam which pressured the transmission to the point that fluid pushed the dipstick out of the tube and on to the hot exhaust, which then ignited. Luckily I was already stopped and had the hood up when it started burning. I was able to get it out quickly with no damage but I would rather not try my luck again.

70W-32

Right Stuff detailing and Classic Tube are both better sources for pre-bent tubing

4speed455

So I got the ones listed for a 72 in stainless from inline tube and installed them today. Apparently the upper fitting is lower on 72 so the line had a shorter drop, which I think actually helped me because I ran the lines above the control arms to clear the headers. The longer drop would have pushed the line down lower and possibly interfered with the control arm. It was fairly easy to bend the lines to give me plenty of clearance for the headers.