LQ4 Recommendation Request
11-15-2019, 02:26 PM
#1
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LQ4 Recommendation Request Hi all
I think this is my first post on LS1Tech but as usual I've been reading here for years.
I have done lots of searching on my topic but there are always some specific questions for each build. I'm building an LQ4 that will keep the whole stock bottom end. I'm planning to run 706 heads for their cheap price and small chamber volume to bring the compression ratio up to around 10.4:1 with factory MLS gaskets.
I plan on using ls6 springs so the only big thing left to decide is the cam. The comp cams xr265hr is one I think fits the bill but want your opinions.
This engine will be in a 1970 Jeep Gladiator J4000 that weighs around 5500lbs and is on 37" tires so it's never going to be a race car. Low end torque is more important and this won't run past 6k very often. It will be a weekend cruiser and offroad toy. Towing would be mild if any.
I also have a set of long tube headers to help keep the more vintage sound for a 50 year old truck.
I think this is my first post on LS1Tech but as usual I've been reading here for years.
I have done lots of searching on my topic but there are always some specific questions for each build. I'm building an LQ4 that will keep the whole stock bottom end. I'm planning to run 706 heads for their cheap price and small chamber volume to bring the compression ratio up to around 10.4:1 with factory MLS gaskets.
I plan on using ls6 springs so the only big thing left to decide is the cam. The comp cams xr265hr is one I think fits the bill but want your opinions.
This engine will be in a 1970 Jeep Gladiator J4000 that weighs around 5500lbs and is on 37" tires so it's never going to be a race car. Low end torque is more important and this won't run past 6k very often. It will be a weekend cruiser and offroad toy. Towing would be mild if any.
I also have a set of long tube headers to help keep the more vintage sound for a 50 year old truck.
Last edited by TurboJ4000; 11-15-2019 at 04:17 PM.
11-15-2019, 05:47 PM
#2
Drop in truck cam would be the best choice for you, they have a primary focus on low end power for heavy vehicles, and they still offer large gains throughout the rpm range.
But the high lift truck cams (600 lift) make more power everywhere in the rpm range than the low lift ones do (520-550) lift so I would for sure do the high lift. But that means going to a better spring than the LS6 spring. You can do the LS6 springs and a real mild low lift truck cam though. I wouldn't.
Look at texas speed truck cams. I would do the stage 1 or stage 2 for your setup, and do the high lift.
But the high lift truck cams (600 lift) make more power everywhere in the rpm range than the low lift ones do (520-550) lift so I would for sure do the high lift. But that means going to a better spring than the LS6 spring. You can do the LS6 springs and a real mild low lift truck cam though. I wouldn't.
Look at texas speed truck cams. I would do the stage 1 or stage 2 for your setup, and do the high lift.
11-15-2019, 06:36 PM
#3
I would never run stock springs on anything but a stock cam.
If you run an aftermarket cam, you need the right springs. Your cam card should tell you what open and closed seat pressures you need.
If in doubt, talk to a good builder. They will point you in a good direction about what springs to use.
If you run an aftermarket cam, you need the right springs. Your cam card should tell you what open and closed seat pressures you need.
If in doubt, talk to a good builder. They will point you in a good direction about what springs to use.
11-16-2019, 03:05 PM
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Drop in truck cam would be the best choice for you, they have a primary focus on low end power for heavy vehicles, and they still offer large gains throughout the rpm range.
But the high lift truck cams (600 lift) make more power everywhere in the rpm range than the low lift ones do (520-550) lift so I would for sure do the high lift. But that means going to a better spring than the LS6 spring. You can do the LS6 springs and a real mild low lift truck cam though. I wouldn't.
Look at texas speed truck cams. I would do the stage 1 or stage 2 for your setup, and do the high lift.
But the high lift truck cams (600 lift) make more power everywhere in the rpm range than the low lift ones do (520-550) lift so I would for sure do the high lift. But that means going to a better spring than the LS6 spring. You can do the LS6 springs and a real mild low lift truck cam though. I wouldn't.
Look at texas speed truck cams. I would do the stage 1 or stage 2 for your setup, and do the high lift.
Aright well I haven't bought any springs yet so may as well get the bigger ones. Factory 706 heads should be able to use the factory length push rods but Ill check that when I assemble it.
Any hints on the fuel system? I have not tuned any FI stuff before but I've read the lq4s were pretty close to max on the injectors factory? But other say they make 500hp on the factory injectors.
12-11-2019, 07:26 AM
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Well I ordered the TSP Stage 3 High lift truck cam during their black Friday sale. 216/220 0.600/0.600. Should be a very fun truck when its done. When I talked with TSP about the stage 2 vs stage 3 question it came down to how much will this truck be towing and since it will be pretty rare I went with the bigger cam. I would like to get a higher stall converter as well so that and injectors is the next problem to solve.
The engine fired up in stock form for the first time since I reworked the factory harness so that is pretty exciting. Now its time to tear it apart and swap heads and cam and give it a refresh with new seals and paint.
The engine fired up in stock form for the first time since I reworked the factory harness so that is pretty exciting. Now its time to tear it apart and swap heads and cam and give it a refresh with new seals and paint.