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Unread 04-13-2013, 01:44 PM   #1
89YJBuilder
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351W build

I just acquired a 351W to use to replace the squirrel brigade in the YJ. I am thinking about what I should do in the build of the engine for torque. I am not wanting a 300hp. 200 - 275 is plenty for me, how ever I want all torque I can get and maintain decent mileage. I am dealing with an 85 engine that is carbed for now. Eventually I would like to do a Holley or Howell tbi conversion on it. Also the cost is a major factor in this build. I also am working on the NP435, NP 205 and 9" rear that will be used. I expect this to take almost two years to get all of it ready to install.

So, opinions please.

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Unread 04-15-2013, 07:04 PM   #2
jeepdaddy2000
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Stock Motorcraft or a small 4bbl on a dual plane manifold.
RV cam.
High volume oil pump.
Retain or install an electronic ignition.
Bump up the timing to 10 degrees or so.
That is about it.
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Unread 04-15-2013, 08:17 PM   #3
89YJBuilder
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Great info thank you.
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Unread 04-15-2013, 08:41 PM   #4
89YJBuilder
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On the timing issue do you mean 10 past factory setting or 10 total?
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Unread 04-16-2013, 03:59 PM   #5
jeepdaddy2000
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10 BTDC at idle, no vac adv. You can drive it and play with it a bit. Just be sure to bump it back if it starts to ping under load. A 351W will put out plenty of power in stock trim.
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Unread 04-16-2013, 08:32 PM   #6
89YJBuilder
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Okay thanks, I have been needing to look up the hp and ft/lbs. I would be very happy with 200-275hp and 275-300ft/lbs. I am replacing a 2.5l so stock will be a huge improvement. I may just balance the rotating assembly, rebuild the carb, polish & port the heads. Replace rings and bearings and maybe a new cam. Check the lifters and valves and replace as needed. Of coarse I'll cut the ridge and hone the cylinders and only bore if needed. Have the block tanked, mains and cams align honed, squared and maybe decked for a little more compression (i.e. 9:1) and then have the head mounting surfaces trued. Manifolds are really rusty so I may have them sand blasted as well as trued that is if i don't do headers. I've been told that the Windsor heads breath really well.
I had thought about going .20 over, doing a full roller valve train with a valley girdle, Cloyes gear drive, a little more cam, change it over to a Holley TBI and use a Torquer II manifold.
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Unread 04-17-2013, 05:10 AM   #7
jeepdaddy2000
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If you are going that deep, you might as well bore (true) the cylinders. .030 is a standard first cut. I would skip the balancing, P&P'ing the heads, line boring the bearings, valley girdle, roller cam, etc....
Unless you're planning on seriously flogging the engine, I would opt for a standard rebuild.
.030 pistons and true the bores
Reground crank (usually .010/.010)
All new bearings/seals
Tank the block, heads, and all tin
Complete head rebuild.
An intake/cam/ carb(FI) combo that complements each other and fits the application. This is important. Most folks try to go big here and wind up with poor performance and a lot of issues that simply can't be fixed without going in and replacing a lot of expensive componentry. I prefer a small carb (400 to 500 CFM)on a dual plane low rise manifold with an RV grind cam. This gives excellent starting, smooth idle, good mileage, will pull off idle, and won't break the bank.
You can go a bit bigger and work toward the mid RPM range, but again, get a combo that will work together.
Pick the RPM band you want to do your wheeling in and build for that area. Most folks run their engines below 4K virtually all their life, with the working meat of the power band falling off idle to the 3K zone. Only on rare occasions do they "get into it".
These are just my personal views, but they have always worked for me.......
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Unread 04-17-2013, 01:00 PM   #8
89YJBuilder
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I agree with your thoughts. That's the rout I have always taken on DDs. I Kinda wanted something different. I have always wanted to do a full roller valve train and I always wanted to do a gear drive. I guess they are left over desires from my muscle car period. I probably won't do either on this engine but I still think about it. I will more than likely do the P&P on the heads because it helps build torque and more than likely I will run shorty headers. I will tank and pressure test the heads if they need it they will be rebuilt. I am definitely tanking the block having it squared and trued and decked. I want 9:1 comp ratio. I get new valve covers and clean the others. Of course I will repaint before assembly. I will stick with the factory 4bbl carb, though I think I will do a different intake manifold. I am as well looking at a new cam. I could never get a grasp on the specs they give on them so I figured I would talk to a Jegs tech support person about matching the cam and intake to the carb. I may ask them about the Holley Truck Evenger carbs.
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Unread 04-17-2013, 11:47 PM   #9
89YJBuilder
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I have decided on the intake and valve train.

Carburetor will be a Holley Truck Avenger 670cfm #510-0-90670
Intake manifold will be an Edelbrock Performer #350-3783
Cam will be Comp Cams Xtreme 4x4 K35-231-3 kit with lifters, springs, keepers, locks, shims, timing gear and chain set
Pistons will be Seal power #844-L2446F30 .030 over

The carb will have to work for a while untill I can afford a TBI conversion, but when I get the money I will convert it.
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Unread 09-04-2013, 08:28 PM   #10
89YJBuilder
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once again every thing with the power plant has changed. I have found out from Holley that the truck avenger carb is great off road however, it sucks gas on the street and you can not tow with it as it has no high speed air bleed. that will cause the engine to load and foul until it dies. A standard carb doesn't work for off road use as they can't handle very off camber situations. I am a off camber guy as some of you know.
So that being said I am going to pick n Pull in Windsor to hunt for a OBD1 5.0l from a Exploder. They are already injected and maybe a runner that just needs a little tlc. They ask $178 for a complete engine with accessories. It was estimated $1900 for machine work, no parts, for the 351W plus minimum of $2300 for an aftermarket efi.
Long story short I am in the market for a running Explorer or F series 5.0l. still running the other drive train. and I think I want to find a front axle with the same width as the full size Bronco 9". I'll just use the back space to adjust width what I can.
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Unread 09-05-2013, 06:17 AM   #11
vadslram
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My 69 mustang had a Windsor before I swapped it out for a 428.
I put in a marine, longer duration cam and a vacum secondary 4 bbl Holley. On the other end I had a custom set of 4 to one headers and kept the exhaust 3 inch all the way back. The bus shop I had the pipes bent at had fits getting it right. Once it was done though it was fairly quiet at idle and had enough BP to keep the valves from burning out. The longer duration gave all the breathing without the high lift lope.

It's going to be a little wide for the YJ engine bay. You might need to do some sheet metal mods. When I put in the SCJ I had to mod the shock towers and still had to lift the engine to change the back plugs.
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Unread 09-05-2013, 01:56 PM   #12
89YJBuilder
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I preferably would like to get a 5.0l it was the original build plan. I was gonna use the 351w because I had it.
The marine cam, did that have good or bad mileage on the street. I will still be driving it to and from the trails. I had thought about using one do to the low rpm torque curve as I understand them. I am not very knowledgeable about cams other than the basics. I have never had anybody explain to me about the mechanics of the specs. Meaning that when they list the amount of lift, duration and separation, I don"t get how they relate to what builds better torque or horse power. Which would have more power at higher rpm. I do understand the individual specs of how much lift is being accomplished, how long the valve is held open, and how much time there is between opening one and then the next.
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Unread 09-05-2013, 02:35 PM   #13
vadslram
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Any time you get more air and fuel to make power you will lose some ecomomy.
But I think you won't notice much of a loss over current since now you need 80% of total capacity at hwy speed a 351 would be running less than half.
A 289 or 302 boss would be lighter and smaller but it depends on what you got. All three are basically the same block.

The marine cam just held the valves open longer to give better breathing but it wasn't radical. I needed it as my DD so drivability was top concern. A high lift cam opens the valves higher but later and it makes the charge swirl a bit more at speed but at idle it isn't so good. You've heard muscle cars with that lope in the idle that sounds like it wants to stall...high lift. the long duration letsthe valve open as soon as the intake stroke starts reducing the vacum drag on the cylinder and giving a full cool air fuel charge.
I was getting ~19 mpg as long as I stayed out of the secondaries.

BUT
Don't go by just "high lift" or "marine"! best bet would be to use the cam mfr web sites and get them to tell you which lobe profiles are best for your engine/intake/exhaust and car weight combo. They will be glad to tell you, it's how they sell their product.
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Unread 09-06-2013, 01:57 PM   #14
89YJBuilder
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Thanks that helps alot. I can see how opening earlier would be beneficial. I am very familiar with the lope that a strong cam makes. I had a 68 Charger R/T 440 six pack. She ran 15 second quarters at Sears Point when I was in high school. It was my life. I had only to get it painted and she would have been complete. While in basic training a drunk driver crashed through the back fence hitting and totaling her. The frame was bent in over 3 inches. I love that sound a hot cam makes. I thought about putting a Comp Cams Thumper in the 5.0l with a gear drive just so I had a little memory of the Charger. I know, I Know not good for off road but it would be a little connection to a lost love.
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