radiator hoses for a LT1 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

CustomMike · 07-29-2004, 04:36 PM

I have installed a LT1 in a 1972 4x4. I would like to know how others with a LT1 have hooked up the radiator hoses since you have different size outlets on the water pump and stock radiator.
Mike

jorgensensc · 07-29-2004, 06:29 PM

Personally I suggest geting an aluminum radiator to help cool it down a little. You can pick up a used camaro radiator pretty cheap if you look around. if you really want to use the radiator you have you can take the smaller of the two inlets, put the hose that fits on it over the inlet, cutthe hose flush with the inlet, then slide the bigger hose over the top of that hose. You might have to put some KY Jelly on it (Don't laugh, I keep some liquid KY in the toolbox, it works great and doesn't hurt anything). be ure and clamp it down tight and it will work just fine. That's how mine is setup on my engine, with a newer radiator.

Wootdog · 07-29-2004, 06:43 PM

For the bottom hose I went to a place that makes hoses. I bought an adapter that is 1 1/4" on one end and 1 3/4" on the other. Then I connected the hoses to the water inlet and the bottom of the radiator. You will have to shorten the two hoses to put the adapter in there. By the way I also put a T for the fitting/hoses to the back of the heads. I believe it is called a steam pipe. To elaborate, the T goes between the adapter and the water inlet on the front of the engine. Hope that makes sense. Kerry

CustomMike · 07-29-2004, 10:05 PM

Thanks for the responses. I have a brand new four core radiator so I don't think I will have cooling problems. Wootdog Did you put the tee for the steam vent in the lower or upper hose? Does it really matter where it dumps? On my Corvette it dumps in the radiator. I was planning to dump it in the top hose. What did you do with the upper hose to make it fit? Did you use the 1 1/4 hose and heat and stretch it over the top 1 1/2 radiator fitting? What hoses did you use to connect? did you just go to the parts store and pick and chose what looked right or did you ask for something specific? I tried some flex radiator hoses that had the two different sizes but they didn't work well at all.
Mike

jorgensensc · 07-29-2004, 10:09 PM

Just a thought: Is it possible to weld on an exhaust type reducer? That's what I used when I did my rear gas tank conversion since the filler necks were different sizes.

maynardogle · 05-15-2020, 03:54 PM

I just finished putting a Champion 3 row radiator in my 68 C10 with LT1 engine. The radiator hoses were a bit of a challenge but I finally got it figured out. The bottom hose is a Gates 21055 which 1.75 on the radiator side and 1.5” on the thermostat housing. It fit perfect with no trimming. The top hose is Gates #20607, which is 1.5” on both ends. The top hose required substantial shortening on both ends to fit right and I installed a sleeve in the middle with a 3/8 hose barb for the steam line.. Both these hoses need to be installed with a 1.25 to 1.5 sleeve adaptor on the water pump end. The Gates number on the adaptors is #263900.

weq92f · 05-15-2020, 04:00 PM

.
Got pics? You sticking with the Opti-Spark or using some other type of ignition? What tranny?

I lived with an LT1 for over two decades so I'm curious.

-klb

**jayoldschool** · 05-15-2020, 05:28 PM

Assuming we're talking 92-96 LT1, you need to remember that it is reverse cooled.

68shortwide · 05-17-2020, 01:05 AM

Bookmarked in case I get the itch to use one of my spares, thank you.

maynardogle · 07-14-2020, 07:15 PM

Quote:

Originally Posted by weq92f

.
Got pics? You sticking with the Opti-Spark or using some other type of ignition? What tranny?

I lived with an LT1 for over two decades so I'm curious.

-klb

I ditched the 20 year old fuel injection and went back to f barrel carb. GM Performance manifolds has a hole for the distributor and I chose a Pertornix Flamethrower II and matching coil. No more computer, no more Optispark.

Tranny is 700R4 with TV cable control.

Pictures attached.

weq92f · 07-14-2020, 11:31 PM

Quote:

Originally Posted by maynardogle

I ditched the 20 year old fuel injection and went back to f barrel carb. GM Performance manifolds has a hole for the distributor and I chose a Pertornix Flamethrower II and matching coil. No more computer, no more Optispark.

Tranny is 700R4 with TV cable control.

Pictures attached.

.
Look at that...nice. It's a stout motor!

-klb

Warrens69GMC · 07-14-2020, 11:41 PM

Nice

07-29-2004, 04:36 PM	#1
CustomMike Registered User Join Date: Oct 2002 Location: Harrisonburg Va Posts: 12	radiator hoses for a LT1 I have installed a LT1 in a 1972 4x4. I would like to know how others with a LT1 have hooked up the radiator hoses since you have different size outlets on the water pump and stock radiator. Mike

07-29-2004, 06:43 PM	#3
Wootdog Senior Member Join Date: Jan 2001 Location: Virginia Beach, Va, USA Posts: 1,676	For the bottom hose I went to a place that makes hoses. I bought an adapter that is 1 1/4" on one end and 1 3/4" on the other. Then I connected the hoses to the water inlet and the bottom of the radiator. You will have to shorten the two hoses to put the adapter in there. By the way I also put a T for the fitting/hoses to the back of the heads. I believe it is called a steam pipe. To elaborate, the T goes between the adapter and the water inlet on the front of the engine. Hope that makes sense. Kerry __________________ 1969 Chevelle 1990 IROC Z Convertible 2002 Silverado LT

07-29-2004, 10:09 PM	#5
jorgensensc Registered User Join Date: Jul 2003 Location: Cypress, Tx Posts: 4,005	Just a thought: Is it possible to weld on an exhaust type reducer? That's what I used when I did my rear gas tank conversion since the filler necks were different sizes. __________________ 1972 C20 Suburban- Big Blue Betty '56 Chevy Bel Air Sedan- Frame up Restoration -What would you attempt to achieve if you knew you could not fail?- -I Refuse To Tiptoe Through Life, Only To Arrive Safely At Death's Door- R.I.P. EAST SIDE LOW LIFE

05-15-2020, 03:54 PM	#6
maynardogle Registered User Join Date: Mar 2017 Location: Huntington Beach, CA Posts: 17	Re: radiator hoses for a LT1 I just finished putting a Champion 3 row radiator in my 68 C10 with LT1 engine. The radiator hoses were a bit of a challenge but I finally got it figured out. The bottom hose is a Gates 21055 which 1.75 on the radiator side and 1.5” on the thermostat housing. It fit perfect with no trimming. The top hose is Gates #20607, which is 1.5” on both ends. The top hose required substantial shortening on both ends to fit right and I installed a sleeve in the middle with a 3/8 hose barb for the steam line.. Both these hoses need to be installed with a 1.25 to 1.5 sleeve adaptor on the water pump end. The Gates number on the adaptors is #263900. Last edited by maynardogle; 05-15-2020 at 03:55 PM. Reason: Syntax errors

05-15-2020, 04:00 PM	#7
weq92f Registered User Join Date: Oct 2016 Location: Dallas Texas Posts: 3,049	Re: radiator hoses for a LT1 . Got pics? You sticking with the Opti-Spark or using some other type of ignition? What tranny? I lived with an LT1 for over two decades so I'm curious. -klb __________________ 67 C10 fleet fuel injected '70 402, 700r4, 3.73 posi 07 335 sport turbo 6sp 94 Trans Am GT LT1 6sp posi -- sold after 22yrs 99 540 sport V8 6sp -- sold 73 240z L24 4sp -- given to friend 68 C10 step 350/350 3.73 open -- sold

07-29-2004, 06:29 PM	#2
jorgensensc Registered User Join Date: Jul 2003 Location: Cypress, Tx Posts: 4,005	Personally I suggest geting an aluminum radiator to help cool it down a little. You can pick up a used camaro radiator pretty cheap if you look around. if you really want to use the radiator you have you can take the smaller of the two inlets, put the hose that fits on it over the inlet, cutthe hose flush with the inlet, then slide the bigger hose over the top of that hose. You might have to put some KY Jelly on it (Don't laugh, I keep some liquid KY in the toolbox, it works great and doesn't hurt anything). be ure and clamp it down tight and it will work just fine. That's how mine is setup on my engine, with a newer radiator. __________________ 1972 C20 Suburban- Big Blue Betty '56 Chevy Bel Air Sedan- Frame up Restoration -What would you attempt to achieve if you knew you could not fail?- -I Refuse To Tiptoe Through Life, Only To Arrive Safely At Death's Door- R.I.P. EAST SIDE LOW LIFE

07-29-2004, 10:05 PM	#4
CustomMike Registered User Join Date: Oct 2002 Location: Harrisonburg Va Posts: 12	Thanks for the responses. I have a brand new four core radiator so I don't think I will have cooling problems. Wootdog Did you put the tee for the steam vent in the lower or upper hose? Does it really matter where it dumps? On my Corvette it dumps in the radiator. I was planning to dump it in the top hose. What did you do with the upper hose to make it fit? Did you use the 1 1/4 hose and heat and stretch it over the top 1 1/2 radiator fitting? What hoses did you use to connect? did you just go to the parts store and pick and chose what looked right or did you ask for something specific? I tried some flex radiator hoses that had the two different sizes but they didn't work well at all. Mike

05-15-2020, 05:28 PM	#8
jayoldschool Moderator Join Date: Dec 2012 Location: ON, Canada Posts: 2,156	Re: radiator hoses for a LT1 Assuming we're talking 92-96 LT1, you need to remember that it is reverse cooled.

05-17-2020, 01:05 AM	#9
68shortwide Registered User Join Date: Jul 2014 Location: Missouri Posts: 1,427	Re: radiator hoses for a LT1 Bookmarked in case I get the itch to use one of my spares, thank you. __________________ Jack Personal Fleet: Family Fleet: 1955.5 Panel 1959 Apache 1968 ShortWide 1969 ShortStep

07-14-2020, 11:41 PM	#12
Warrens69GMC Registered User Join Date: Jan 2003 Location: Safford,AZ Posts: 3,613	Re: radiator hoses for a LT1 Nice



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