Your donations help keep this valuable resource free and growing. Thank you.
|
304 |
Post Reply | Page 12> |
Author | |
66rebel
AMC Apprentice Joined: Feb/05/2012 Location: uk Status: Offline Points: 57 |
Post Options
Thanks(0)
Posted: Jul/20/2014 at 2:31am |
Ok, i have got a 304 and bw trans out of a 70 rebel, motor is going to have a complete overhaul.
Before we all jump in and say get a 360 consider the fact i am in the uk and parts are not readily available for amc cars at all. So i am stuck with the 304! Its going in my 66 so it will be a major improvement on the stock 232. SO A FEW QUESTIONS. 1. CAN I RUN 290 PISTONS? If so what will it bump compression up to? 2. WHAT WOULD BE A GOOD CAM CHOICE? I would like to take it to the strip and have a little fun rear end is a ford 8,8 with 4 10s. 3. if pistons are a no go how much can i take off the heads and block before piston hits valve? |
|
limachine
AMC Apprentice Joined: Apr/02/2009 Location: Long Island Status: Offline Points: 151 |
Post Options
Thanks(0)
|
Well, you could use the 290 pistons, both have the same bore. But compression ratio will depend on the style of piston. I remember the flat tops were higher (10 to 1). I don't remember seeing domed pistons. I'm not a machinist, so someone's gotta back me up here, but I remember some guys that used to run 304 engines punched out 0.125" with high compression 6 cyl (4.0L) pistons? I also remember someone running Chevy pistons...don't know how available they are across the pond, or how easy that setup is.
Good luck |
|
crazyamc
AMC Apprentice Joined: Jan/08/2012 Location: Texas Status: Offline Points: 70 |
Post Options
Thanks(0)
|
I believe the advertised compression ratio difference is in the deck height/chamber volume difference... It's been a little while, but I remember doing the math and discovering that the longer stroke 304, in the taller block, with the bigger chamber head, makes it and the 290 piston virtually the same.... basically, a " 9 to 1 304 piston" is a " 10 to 1" 290 piston...... I could be wrong though- it has happened on rare occasions.. :)
|
|
Ronnie Kaplan Engineering :)
|
|
Boris Badanov
AMC Addicted Joined: Dec/14/2013 Location: NH USA Status: Offline Points: 4209 |
Post Options
Thanks(0)
|
A 1970 304 is a pretty strong motor as it is.
If your boring it just get flat top single valve relief piston and a mild cam in the 270 degree advertized duration range. Depending on head casting number you could net about 10:1 to 11:1 compression. Sounds like you are on a tight budget, but there is a lot you can do with a 304. |
|
Gremlin Dreams
|
|
limachine
AMC Apprentice Joined: Apr/02/2009 Location: Long Island Status: Offline Points: 151 |
Post Options
Thanks(0)
|
Hey 66Rebel, (in case you didn't know and if you did I apologize) Summit Racing ships internationally (located in Ohio, USA) they are always very helpful to me and can be contacted online through their site, good prices, they got me through my 390 rebuild.
|
|
wantajav
AMC Addicted Joined: Sep/04/2009 Location: PA Status: Offline Points: 1150 |
Post Options
Thanks(0)
|
Sir:
My comments as useful or useless as they may be: basis for my comments: I have a 304, a 290, a 343, and two 360's in various stages of disrepair. If you are sticking with the 304 : 1.304= Good stout engine 2.See if you can ball-hone and re-ring it, that will be your best option 3.304 stock vs 304 lively = better exhaust (headers), better intake (aluminum from summit and carburetor), mild cam (summit) and improved ignition (summit) 4.If the Borg Warner still works -by the way M35 used in LOTS of Jaguar saloons -go with that 5.Rear gear -can you swap in a set around 3.54 if you have the 2.87 rear otherwise don't bother for a 250 hp street car on stock tires one single compression point on a mostly stock engine won't get you much the 290 and a 304 had pretty much the same CR one point extra = 10-20 hp then it will knock above 10:1 on iron heads anyway use the high zinc oil at all times -not today's oil Mike |
|
gremlinsteve
AMC Addicted Joined: Dec/16/2008 Location: houston Status: Offline Points: 884 |
Post Options
Thanks(0)
|
Or keep the low compression and try to build cyl pressure so it will run decently enough to justify a cam swap.
I used a 261/267 lobe on a 108 las and had four degrees advance ground it. So she comes in at a 104. That should work fine with a 8.4 304 on pump gas. |
|
66rebel
AMC Apprentice Joined: Feb/05/2012 Location: uk Status: Offline Points: 57 |
Post Options
Thanks(0)
|
I got another plan, i also have a 360, i have been told the 304 and 360 cranks are the same is this true?
The big issue for me on this build is that i had a 360 and a th400 from a jeep i know about the tailshaft problem with the jeep having a transfer box, so i bought a 70 rebel. it is a 304 well was until i pulled the motor! But now i am looking at my 360, it appears that the BW trans will mount to it but if i am correct the 360 crank cant be used without modification but if the 304 crank is the same i can swap it into the 360 right? |
|
Boris Badanov
AMC Addicted Joined: Dec/14/2013 Location: NH USA Status: Offline Points: 4209 |
Post Options
Thanks(0)
|
304 crank and rods are a perfect match.
Depending on the year of the 360 you may
want to swap the crank.
Use the 304 crank with the 360 harmonic balancer
and flywheel/flex plate.
The only thing i am not sure of is the bolt pattern on the flex plate
matching the BW converter.
|
|
Gremlin Dreams
|
|
SC397
AMC Addicted Joined: Apr/30/2009 Location: Michigan Status: Offline Points: 5428 |
Post Options
Thanks(0)
|
Post Reply | Page 12> |
Tweet
|
Forum Jump | Forum Permissions You cannot post new topics in this forum You cannot reply to topics in this forum You cannot delete your posts in this forum You cannot edit your posts in this forum You cannot create polls in this forum You cannot vote in polls in this forum |