Max Bore AMC 304 Build Begins! Short Block Prep and assembly!

It's been a long long time since we started this AMC 304 build but the block is finally back from the machine shop and it's time to get cranking! Our previous 304 AMC V8 build was more of a "budget build" with .060 pistons, a lightly improved cam shaft, intake, carb, and basically stock 304 heads. This time we're reaching for a little more, going to the "max bore" of the AMC 304 block at .125 over, which also allows us to use a set of Jeep pistions +2! In addition to that we're now going to be running a set of AMC 360 heads allowing us better flow and bigger valves!
Unfortunately even after the machine shop work was completed, we still have some block modifications to do to improve oiling and cooling. One of the known weak points of the AMC V8 are oiling short falls especially when put under stress of motorsport or long drives. With on and off track shenanigans ahead as well as 2000ish miles for Hot Rod Power Tour 2023, we certainly don't want to be worrying about a freshly built motor! Oh and if things needed to be a TINY bit more stressful, we need this motor assembled and in the car even earlier to try to have it ready for Great AMC Day on June 2nd at Edgewater Motorsports Park in Cincinnati! Noooo pressure at all!

[@jamesroberts1800]

I'll be very surprised if there is any oil pressure at all after hogging out those passages with a drillbit .... I'd say you created a 30% or so larger passage and it will create all sorts of problems. And yet....he didn't bother to smooth the passage from the front cover passages into the block....those are the problem areas on a AMC. I used to work at a AMC dealership when that car was new and under warranty. Tip: look in the factory parts book for the "Group 19" engine options, those are all the factory made Hi-Po parts.....solid cams, adj rockers, dual quad intake, distributors, etc etc. AMC made a ton of factory available Hi-Po stuff....you just need the part numbers to find them, guarantee they are out there because no one knows what they are for. I was cited for 167 mph in my old Javelin on hwy 15E in Cali back in the day, I know how to make them run :)

[@kennethcohagen3539]

I agree with your assessment on oiling. But now that that’s done, what do you think the Indy Cylinder Heads Pump assembly would do. It’s larger that stock and the one for factory blocks is larger than the one for their Aluminum block. (If I was rich!) will the extra pump volume help?

[@scottrance-im7xz]

Totally agree this routinely drilling oil gallery passages bigger is not the great idea everyone is copying on their AMC builds. The issue on AMC blocks ONLY is there some issues where the holes in block main saddles require the drilling to get down into the lifter oil gallery to ensure the oil passage are drilled clear through . There are blocks where the passages on the mains were not cleanly drilled all the way into oil passages feeds from lifter oil passages , but not ALL . Always check . However this whole opening up all the oil holes to a 5 /16 " or more does allow more unrestricted flow but at the expense of oil pressure . Larger oil galleries reduce the oil pressure especially if you drill bearing holes bigger . Think of this like having excessive bearing clearance . .001 to .002 for example on mains 1 thru 4 , if those clearances are increased to .003 your oil pressure goes DOWN . Smaller oil passages keep pressure higher. The larger you drill the passages, you lose pressure . Now if you do not drill out your mains oiling holes , and do not drill out your rod or cam bearing oiling holes , you can keep oil pressure up . Never enlarge bearing holes as they are small to RESTRICT oiling to keep oil pressure within specifications ... Anyone notice just how many AMC V8 engines all have low oil pressure on new rebuilt engines . JEEP FORUMS and AMC forums routinely have many many postings of new engines with 10psi hot idle oil pressure . NO its not ok and not normal , unless all this oil passage enlarging going on has ruined the oil pressure capability.

[@olsketchmo]

Block Lifter Bore fit and finish? Was anything done to the lifter bores AFTER the front-to-back Drilling of those two passages that intersect all the lifter bores, do they not? Might there have been maybe a little flashing or whatever in the lifter bores at the cross-drill intersection? Also, be sure and measure the lifter bores and the lifters to check the fit and clearance, finding too much due to part consolidation is not uncommon. Keep up the good work. Thank you.

[@kurtblackwell6214]

Having grown up in Kenosha, I've been exposed to AMC's most of my life. I remember the old guys saying about AMC motors: "They always run, usually not good, but they always run," and "You could take a piston out of an AMC 6 and it would still run!" Not surprised the old 304 ran with round cam lobes! LOL

[@lonniemiller757]

I bought a304 in a javelin. Everything was in the oil pan Zero oil pressure And it ran sounded like hell. I scraped everything but it had 360headson it valves were hitting the boar. Nuts but I saved the hie flowing heads.

[@LucoreAuto]

Unfortunately those little 304s almost never got taken care of especially in the later days of their lives. They are good little motors just never got much love because of their big brother 360s which fit in the same hole.

[@kennethcohagen3539]

I’ve been trying to research a build like this! What I’m really interested in is what heads can be used on this. does this max bore engine accept any aftermarket heads? will it accept 360 heads? Both of these are possible if the valves are centered in the bore like a Mopar A engine. If they offset like most other engines, it may not.

[@LucoreAuto]

Indeed Sir they will, and with going this car on the overbore should also get rid of MOST of the "valve shrouding" issue. Also going to a 360 head gives us bigger valve AND more available lift. Soooo, could be a fun lil 304! (we hope)

[@brucefrye8799]

That block must have came from the southwest for some reason they use only water in the cooling system

[@riffrebel4658]

Why not tap into the oil bulkhead at the front of the motor & connect an oil line to the back (#8) cylinder to help the oiling of the mains?

[@Rockit401]

That is the way it was done in the olden days. Seems to work fine.

[@WiSeNhEiMeR-1369]

= on my RACE Engine = 310ci AMC V-8 ( 9,250 RPM Shift Point ) I ran a BIGGER very L O N G Drill Bit from the FRONT of the BLOCK ... back to the Threaded HOLE for the Oil Pick-Up tube ( 1/.2" to 5/8" or maybe 5/8" to 3/4" ) it has been too long since I did this but it was to allow >MORE oil flow from Oil Pan - to Oil PUMP just an FYI ( & I never ran the under intake oil-line ) COOP

[@patrickmansfield3967]

I do a lot of diesel engines, none of the new bearings come with a tang anymore. I was worried the first time I put one together without the tangs. It’s been fine for about 5 years. 🤷‍♂️

[@warbed1]

Wonder where you learned to drill out the main oil gallery to the lifter gallery with a 5/16 long drill bit and to chamfer the backside of the cam bearings to match the oil gallery because a stock unmodified cam bearing restricts a good 30% of the flow to the mains. I've been telling you I've been doing this for the last 30+ years. Nice to give me a shout out for helping you. Been an AMC lover my entire driving life and one hell of a mechanic. BarberChop is the name Good luck

[@WiSeNhEiMeR-1369]

Tennessee "low" LIFT Custom Camshaft !!! COOP ...

[@justintriplett6573]

I rebuilt my 304 about two weeks ago and the main bearings I ordered from summit came with two thrust bearings with holes and no tangs. I removed the originals from the journals, and they had tangs and a hole on the top side. Weird ....

[@MrRVRclubprez]

Check the oil passages on the timing set, #1 amc problem.

[@brucefrye8799]

I'm really interested in how this engine works if it makes good power I might try this formula myself

[@r.h.5052]

Bearing tang serves no purpose anyhow. Bearing is crush fit once torqued

[@keithfowler6876]

Be interesting to see how much power it produces, the new dyno setup will open the door for more great video content,

[@WiSeNhEiMeR-1369]

HOWdy LUCORE, ... Thanks for the AMC Content & the increased Oiling modifications COOP the WiSeNhEiMeR from Richmond, INDIANA ...

[@jeffjankiewicz5100]

Nice Austin, but why pull the carb off of a running car? Hint...ATM OMG carb. See if Bill can help you out. Excellent work Rich, should be a funner car with that engine. Stay safe all, God Bless.

[@stevecr8934]

Keep an engine guy busy over there. Hope the 304 don't float bearings with larger ports n standard bearing hole. Memorial Day. I'm sure they both Thank our Veterans and military folks for their service to our Nation. Read the Declaration of Independence Monday. It will lift your heart and restore Faith in our Nation under God.

[@jesseevans7974]

What size motor was in the AMC that 304 should have some power

[@LucoreAuto]

THIS car was originally a 304 so we're just reaching for a bit more :) The one that's in the car is fun and makes good noises but was more of a "standard budget rebuild". We're going more towards the wilder side with this one!

[@jesseevans7974]

@@LucoreAuto nice can't wait to see how it does ol Kenny powers will help you break it in lol

[@m620005191]

I HAD 304 73 JAVELIN INSTALLED TORKER INTAKE and 6619 600CFM HOLLEY .RAN GREAT.

[@chrisbryant1657]

Good stuff Rich. Looking forward to the progress on this build. Gremlins and Pacers were common in my high school years. Yeah, I'm getting old. Lol

[@WiSeNhEiMeR-1369]

= I know that you are probably NOT wanting to experiment on this 304 ci Engine but an old SMOKEY YUNICK trick was to place PISTONS 1-3-5-7 into the 2-4-6-8 HOLES & vice-versa because the Piston Pin is slightly OFFSET and this "BANK" Swap holds each piston at TOP-Dead-Center just a fraction of a degree or two l o n g e r & Nets you FREE Horsey-Power COOP ...

[@dbeelee8564]

Interesting. Could you expand on this?

[@truthofgod6213]

The Ross pistons I have, don't signify a cylinder number. I think Smoky was smoking something and pulling your leg.

[@mikeburnett7028]

You guys ready for power tour?

[@terryeustice5399]

Looking good Rich and Austin yes the old cam was trashed. Thanks for sharing! 💯👊👍

[@dave.harmon]

I'm assuming you're gonna fit an updated oil pump to take advantage of the better flow.

[@nonotever-cu3nr]

I have question.maybe you guys have said.anyway are you guy's brothers.

[@kennethchapman9564]

Should make good power and last through the abuse it is sure to see. 👍👍 The old motor was run either with really dirty oil or low oil level and or pressure.

[@alfredodirks3537]

AMC left a lot of meat between the cylinders no chance of head gasket blow out on them!

[@billyray8062]

That engine should have pretty decent power, have fun with it Austin.

[@clydegreenwood5673]

Looks good and keep up with the good work and good luck and be safe and God bless you guys

[@jeffjarquin5600]

The pistons being so low in the bore are gonna give up and quench values what so ever. By the tine you add the head gasket you'll have .075-.080 dead space. You need to deck the block to zero- .010. It will be a lot more detonation resistant and have more compression.

[@olsketchmo]

The pistons end up .025" down in the hole don't they, using nominal dimensions. 9.208" Deck - 1.720" Throw - 5.872" Rod = 1.616" - 1.592" Stk Aftermarket 4.0L Pistons ? = 0.024" Deck Clearance + .043" Gasket = 0.067" I agree, the block deck should be milled and trued, confirmed square and parallel, reduce deck clearance to say .005", improve quench and compression.

[@ECC-ec]

360 502 castings will make it breathe

[@stockamx]

Can't wait for more videos from Edgewater !

[@Fog66]

Wow!!! Big-time blockage

[@eddiebranham8070]

Nice job guy.

[@LucoreAuto]

Still a lot of work ahead of us and not much time to do it!

[@jamiebruce1597]

Looking great you guys!

[@Veryrandy8508]

Is the motor going to run a little hotter with that bigger bore ?

[@truthofgod6213]

Not if he uses a 4 row radiator. It'll just warm up quick. It's how my 401's characteristics ran from the .030 overbore. .025 is max for a 401 according to the AMC Bible (Cpt. America AMC journal).

[@fartking8124]

Why not just build a 360?

[@Whopoopedinmypants]

Went to put main bearings in my 360 and found that i had two cap side thrust bearings lol