Building a 401

[smanley820]

I'm starting to plan my build of a 401 that I aquired a while back. I have read many post regarding all of the issues associated with these motors. That being said I am still going to do it. I have read BJ Builds an AMC and I have some questions that I hope "Jeepsr4ever" will chime in on. This will be in a Jeep that will be running trails and on the street. I'm not building a racer nor will this thing probably see 5000 rpm but I do want the torque and power available. Having said that, I am curious as to what oiling and or block mods you guys would suggest for my application. Just trying to put the best ideas together for my engine so i can get started. I WILL be buying almost all of my parts from Bulltear since all of my research points back to his quality parts. I'm hoping to lean on the expertise of this forum over the next year as I build my engine since I am not an expert in this field. It will not be an short project but will be over a longer period of time. Thank you in advance for all your thoughts and consideration

Scott

[jeepsr4ever]

Their is a short list of things to do. The question is how much is a machinist doing and how much do you plan to do.

[smanley820]

The machinist will 80% Most likely I will bolt it together. Just looking for direction on the best things to do. My main concern is the cam/dizzie gear issues.

[smanley820]

I'm planning on purchasing most of my parts from Bulltear! Most likley everything except the cam

[tufcj]

Since it's a low RPM engine built for torque, I wouldn't do any mods to the block other than bore/tank/clean. I'd put in cam bearings with smaller oil holes, use a mid-plate in the oil pump, and use HRC oil pump gears (all sold here). Turn the crank to the next undersize to be sure the journals are perfectly round, have the rods re-sized and checked for cracks. Have the rotating assembly balanced (well worth the money). Keep the compression in the 9:1 area. AMC engines like to breathe. Get a cam with a lift in the .480-.500 range and a duration of 270-280. Money is well spent on the heads. A mild port and quality valve job will help it breathe. Port match the intake and headers or manifolds. 2 1/2 to 3" exhaust. I've got all these tricks in the 390 I'm building for a 66 Rambler, with a little more compression and a lot more cam for a lot more HP.

You can see pics here: http://www.bulltear.com/forums/showthread.php?19127-Tufcj-s-66-Rogue-Project


Bob
tufcj

[smanley820]

Is it wise to use the Bulltear Cam bearings along with the Bulltear pushrods (increased pressure)?? And also, what do you guys recommend for equipment on the heads? They are a set of 090-1's. Also a question for Jeepsr4ever, is there a benefit to purchasing the timing cover and the Bulltear HEI vs. another? I'm looking to eliminate any possible cam gear/dizzie gear issues.

Scott

[tufcj]

Cam bearings OR pushrods, I wouldn't do both. Also be sure to check that the oil passage in the cam gear is clear of any casting flash so the dizzy gear gets oiled properly. Buy a quality roller timing set. For 090 heads, you can run SBC bolts for the rockers in either 3/8" or 7/16" along with full roller rockers and hardened pushrods. The guide for the pushrod is built into the head. The rockers need to be specific to AMC.

Bob
tufcj

[jeepsr4ever]

Although the website doesnt show it the pushrods in the smaller diameter hole have been discontinued. They along with any other restriction give too much oil pressure.

[smanley820]

Thats good to know, Jeepsr4ever, are there any other tips or tricks that you can recommend to me for building this motor?

[jeepsr4ever]

Fwew where to start.. I would start by keeping in mind your not exceeding 5500rpm. You can run an extra qt of oil in your pan or extra capacity. Other than that to keep the engine healthy a good oil pump system would be where I would start. Check the condition of your timing cover and oil filter adaptor.

[smanley820]

Actually I will be starting with just a short block. I will be ordering Pistons, timing cover/oil pump, cam bearings, HEI & gears from you guys. This engine block was pretty bare when I aquired it so I don't have much. Do you recommend the oil filter adaptor or the remote adapter kit that you sell? The heads will be 090-1's and will be ported and polished witht the scorpion rockers you sell, what about pushrods?? is there anything else?

[smanley820]

Actually I will be starting with just a short block. I will be ordering Pistons, timing cover/oil pump, cam bearings, HEI & gears from you guys. This engine block was pretty bare when I aquired it so I don't have much. Do you recommend the oil filter adaptor or the remote adapter kit that you sell? The heads will be 090-1's and will be ported and polished witht the scorpion rockers you sell, what about pushrods?? is there anything else?



Bump

[smanley820]

Jeepsr4ever, I also have some cam thoughts in mind but I would really like to hear your input or other members input on cam selection for this motor. I know that is a wide ranging & opinionated topic but i just like fresh information.

[jeepsr4ever]

Pushrods need to be hardened for use with guideplates. They are cheap though just 8.14-8.16 5/16" pushrods. The oil filter relocation plate is the best solution to get rid of bottlenecks in the oil system. Fire away with your cam ideas.

[jeepsr4ever]

Is it wise to use the Bulltear Cam bearings along with the Bulltear pushrods (increased pressure)?? And also, what do you guys recommend for equipment on the heads? They are a set of 090-1's. Also a question for Jeepsr4ever, is there a benefit to purchasing the timing cover and the Bulltear HEI vs. another? I'm looking to eliminate any possible cam gear/dizzie gear issues.

Scott

The real deal is we check timing covers for issues so its a "put it together" once build and you dont have to cross your fingers. Also our HEI units are checked as well and made to our specs. There is alot of junk out there and alot of resellers that wont admit to selling junk but get hundreds of complaints that we are easily able to track through customers ordering our matched cam and distributor gear sets.

[smanley820]

Thats the reason I want to go with your timing cover & your HEI/with gears, so they are all matched & tested. I don't want any problems after I get this thing running.

[smanley820]

I know I'm opening a can of worms here but here are my thoughts on cams, I am looking at the Lunati 268/276 or the Comp Thumpr 279. I'm open to listening to all ideas here.

[tufcj]

Bigger isn't better. You said this was for a low RPM, high torque engine. The Lunati will probably let you down just off idle. I'd go a step lower myself. I didn't look at the Comp specs, but I bet they're similar. You might also check Crower, they have a good selection for AMCs. I'm running Crower in both of my 390s.

In my experience, AMC engines do like split duration/split lift cams. With total lifts over .500", pay special attention to clearance between the top of the valve guide and the retainer. .500 is about the max without machining the top of the guide and installing a positive type valve seal.

Give us an idea about the vehicle, weight, trans (and converter if automatic), gearing, and expected use. It all makes a difference in cam selection.

Bob
tufcj

[smanley820]

Ok, here are the specs on the Comp Thumpr cam
http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=1447&sb=2

and here are the Mutha Thumpr cam
http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=1448&sb=0

Let me know what you think

[smanley820]

Bump

[tufcj]

Both of those are more of a street cam. They also have a taller intake lift than exhaust, which is backwards to a torque cam. With a lobe center of 107, you get a lopey idle, but you lose bottom end, I'd keep the lobe center in the 110-112 degree range for torque.. It really looks like you're looking for the sound and not the performance. I had really good luck in my 360 with the 2132 Edelbrock performer, but the new 7132 might be worth a try. The Summit K8600 is also a good torque cam. Cams that don't come in until 2000+ RPM are generally street cams and lack off idle torque.

http://www.edelbrock.com/automotive_new/mc/camshafts/locator.php?part_number=2132&submit=go

http://www.summitracing.com/parts/sum-k8600

Bob
tufcj

[smanley820]

looking for more performance, not loolking for sound necessarily, these were just a few of the cams that i discussed with some of the guys on the jeepForum.com. I'm open to any and all ideas at this point since I have not started yet. Looked hard at the Lunati we spoke of earlier but probably will definately not go with the Summit cams. Why would I lose the low end with these Comp cams?

Thanks

[jeepsr4ever]

More performance with a 401 means more duration. A Comp 268 is the minimum if you want more in the midrange.

[newt]

Have a look at the COMP XE262, Crower 45241, and the Lunati Voodoo 262/268. I think these will give you a good idle for crawling, good throttle responce in the mid range, and enough top end to get you to a healthy 5000 rpm.

But in order for anyone to help you pick the perfect combo, they'll need more info: Comp ratio, tranny, axle gears, crawl ratio, tire size, weight, intended use, etc. What is the wheeling like in your neck of the woods - hilly and rocky crawling or rev limiter bouncing mud holes?