What tire sizes and gear ratios is everyone running? I'm wanting to go to 35's eventually, but have 33's currently.
Magnum engine questions
- Thread starter Gollywomper
- Start date
I started out running 35" tires. I was running a 44RE and 5.13 gears and am now running a 46RE.
And then moved up to 38" tires.
I had the 5.13's with both sizes. As far as what should you run? What axles do you have and what type of wheeling are you gunna be doing?
And what transmission do you have? Auto or manual?
I ran this Rock It intake for a while too. Of course it was suppose to be the Next Best Thing to Sliced Bread back when it first came out.
Ford 8.8 and Dana 30. Mild crawling, exploring and camping (aka various trips to places like Colorado, New Mexico, Arkansas, so on). NV3550 with the 241 behind it. I want to be able to commute and take it on road trips.
I would consider running 4.56 or 4.88 gearing. Remember that will have a V-8 to turn the tires so you don't need to gear it as deep and since you have the 241 & 4:1 low for crawling you don't need deep low gears in your axle.
http://www.grimmjeeper.com/gears.html
Use the Grimm Jeeper gear calculator and play with different ratios. You want your cruising RPM @ 70 MPH to be between 2,500-2,750 for good power without reving the engine too high.
Over on the JeepForum there were some people with manual transmissions who had 4.88 gears and regeared to 4.10 that were running 35" tires. If you've got 33" tires and are going to be going to 35" tires at some point in the future then I'd suggest you wait to regear until you buy the 35" tires.
With a manual trans like yours, I'd go 4.56 for 35"s with the Magnum. I ran 4.88's on my 408-stroker RamCharger with 35"s (and 37"s) but had a 46RH, which has a notably lower (numerically) OD ratio. With your 0.78 OD ratio, you would do well cruising at ~2550 RPM at 75 MPH. You could probably get away with 4.11's but the 4.56 will help better at lower speeds and give a better crawl ratio. IMO, relying on too much help from the 4Lo often makes 4Hi annoyingly under-geared, and you find yourself in positions where 4Lo is too low for the terrain where you need some wheel speed (like mud, rutted out climbs, etc) and 4Hi is too high geared, causing you to shift constantly or not have enough torque multiplication (granted the V8 helps there but you'd rather your multiplication be at the axle vs at the driveline).
OK this was worth sharing and this was a good thread to post it in so a BLAST FROM the PAST....
https://l.facebook.com/l.php?u=http...viMd7z_Fn02G9L_ZyqnJlifZBtz_Xq8g-pYdD_ZHmWE5g
https://www.motortrend.com/how-to/m...U4j4SjvmpoH9TrPM9Hfad29L-ct0PpEAAtraVu2xIcrAg
Small-Block Mopar Engine - Junkyard Jewel 5.9L Mopar Magnum - Engine Buildup — How to Make 450 HP with a Dodge Magnum 360 Truck Engine.
https://l.facebook.com/l.php?u=http...viMd7z_Fn02G9L_ZyqnJlifZBtz_Xq8g-pYdD_ZHmWE5ghttps://l.facebook.com/l.php?u=http...viMd7z_Fn02G9L_ZyqnJlifZBtz_Xq8g-pYdD_ZHmWE5g
https://www.motortrend.com/how-to/m...U4j4SjvmpoH9TrPM9Hfad29L-ct0PpEAAtraVu2xIcrAg
Here's a beautiful setup. Owner has changed his mind and is selling the intake and 53MM TB. This is a hard to find Mopar M1 intake manifold BTW for those that aren't familiar with them.
It had been mentioned before but most times dismissed as being TOO large or not going to fit. Here is a NV4500 behind a magnum V-8 in a TJ. No cutting or pounding of the transmission tunnel required to allow it to fit. I know not the best picture but you can see it is in there.
Here's an article on the magnum intakes & how they flow.
https://www.allpar.com/threads/test...LQeig-UB99TjEfz0Ldwzuu50iBU4VqwHbXluAhGS30VZ8
And a good article by Hughes Engines about performance from the Magnum engine.
https://www.hughesengines.com/TechArticles/4buildingupmagnumtruckengines19932003.php
And a list of articles done by Hughes Engines on the Magnum engines.
https://www.hughesengines.com/TechArticles/magnum_engines_articles.php
Hughes Engines is a Mopar Only shop. They are one of the FEW that has survived over the years. When I did my V-8 swap in 2006 there were about 10 companies that delt with Mopar stuff and some speed shops that specialized in Magnum engines. They are all gone now but you can still find articles or web posts from a few of them.
https://www.allpar.com/threads/test...LQeig-UB99TjEfz0Ldwzuu50iBU4VqwHbXluAhGS30VZ8
And a good article by Hughes Engines about performance from the Magnum engine.
https://www.hughesengines.com/TechArticles/4buildingupmagnumtruckengines19932003.php
And a list of articles done by Hughes Engines on the Magnum engines.
https://www.hughesengines.com/TechArticles/magnum_engines_articles.php
Hughes Engines is a Mopar Only shop. They are one of the FEW that has survived over the years. When I did my V-8 swap in 2006 there were about 10 companies that delt with Mopar stuff and some speed shops that specialized in Magnum engines. They are all gone now but you can still find articles or web posts from a few of them.
Here's another one I think I'd missed before with a good write-up on the install. And he does a cost breakdown also.
Maybe already posted, but I thought this was interesting. I'd definitely be looking this way, if I had an 03...
https://www.motortrend.com/how-to/59l-magnum-engine-make-mine-a-5-9/
https://www.motortrend.com/how-to/59l-magnum-engine-make-mine-a-5-9/
I don't know that I've posted it before but I've read it before. Those are the heads I have on my engine. I have high hopes for them to breath enough for my build.
Edit: Those are the stock valve size heads & I have what they call their Monster heads with a 2.02 intake.
Last edited:
Here's another one with a 417 cid stroker small block making 580 HP. Only 9 ci more than mine.
https://www.motortrend.com/how-to/1304phr-skmfx-budget-small-block/
https://www.motortrend.com/how-to/1304phr-skmfx-budget-small-block/
I was going to ask if you did the head assembly yourself. I've never "built" an engine and its something I've always wanted to do. I've done rebuilds on quite a few small engines, but nothing more than two cylinders. I keep my eyes open for the "right" 4.0L (by right I mean cheap, LOL) to come along so I can build a stroker. I know its probably not worth it in the end, but its something to do during the long, cold winters we have here.
Other than the machine work done by the machine shop I did the full engine assembly. I ground the rings for end gap & measured all the bearings for proper clearance. I'd bought the EQ heads years ago for my other engine build. This was my first real performance engine assembly. I'd rebuilt engines before but they were always stock with maybe a small bump in the cam. It's been a learning experience.
My first engine rebuild was when I was 10 and it was a Briggs & Straiton 5 HP engine for a mini bike. I've been building engines since.
Similar threads
