Lame newbie questions re: Intakes, castings and rocker arms

401 Pacer

Boy howdy do I have some lame-o questions....let me preface this by saying that while I've been a professional mechanic for 30 years there's a lot I don't know about hopping up an AMC V8.

Ferinstance, what's yer take on the following intakes (arranged according to RPM range):

Offenhauser Dual Port
Great in theory, does it actually work?
and in a similar vein:
SP2P
Good for MPG and torque below about 4000 rpm

Performer
I seldom find much power improvement over stock manifolds in general...not even with the stock small block Chevy, and that intake is pretty restrictive. If the price of a used one is cheap enough it may be worth it just for the weight savings!

Performer RPM
Air Gap versus regular Performer (the AG seems to be the way to fly)

R4B
Single plane/open plenum, ancient design, tends to suck gas like a pig

Torker
Single plane/open plenum, slightly less ancient, more fuel efficient but still not very street friendly

I realize that list is all over the map, so allow me to 'splain. Am building a fairly wicked but streetable 401 for a Pacer (stop laughing) but also have a daily driver Matador coupe (I already told you...stop laughing!). The Matador has a tired 304 which I will swap out with a 360.

Obviously the 401 will be getting one of the higher RPM intakes and the 360 will be slated for the economy flavor.

The other question I have is concerning heads, in particular, the style of rocker arms. Which are better suited for performance? I really don't need or want uber expensive mega RPM types, just something reasonably strong and LONG LASTING.

Lastly, are there better years concerning castings (core shift etc) for the blocks and heads?

Thanks!

Note to mods, feel free to move this to whatever section that may be more appropriate.

1980_Cj7

Finally, a 401 Pacer. I luv it!!! Sorry, can't help you much on your questions though.

jeepsr4ever

401 Pacer wrote
Boy howdy do I have some lame-o questions....let me preface this by saying that while I've been a professional mechanic for 30 years there's a lot I don't know about hopping up an AMC V8.

Ferinstance, what's yer take on the following intakes (arranged according to RPM range):

Offenhauser Dual Port
Great in theory, does it actually work? YES
and in a similar vein:
SP2P
Good for MPG and torque below about 4000 rpm Below 3000

Performer
I seldom find much power improvement over stock manifolds in general...not even with the stock small block Chevy, and that intake is pretty restrictive. If the price of a used one is cheap enough it may be worth it just for the weight savings! I find a great improvement with the performer even with the stock carb

Performer RPM
Air Gap versus regular Performer (the AG seems to be the way to fly) I have found it depends on the RPM needed and the amount of vaccum you generate with the stroke you have

R4B
Single plane/open plenum, ancient design, tends to suck gas like a pig True however it is great for midrange AMC V8s and still utilizes the lower area of the intake plenum for fuel/air intake making good lower end torque

Torker
Single plane/open plenum, slightly less ancient, more fuel efficient but still not very street friendly Depending on the camshaft and carb...yes. Keep in mind the entire aspiration system must work together with the cam
I realize that list is all over the map, so allow me to 'splain. Am building a fairly wicked but streetable 401 for a Pacer (stop laughing) but also have a daily driver Matador coupe (I already told you...stop laughing!). The Matador has a tired 304 which I will swap out with a 360.

Obviously the 401 will be getting one of the higher RPM intakes and the 360 will be slated for the economy flavor.

The other question I have is concerning heads, in particular, the style of rocker arms. Which are better suited for performance? I really don't need or want uber expensive mega RPM types, just something reasonably strong and LONG LASTING.

Lastly, are there better years concerning castings (core shift etc) for the blocks and heads? I have found the "502" castings to have the thickest porting areas but need work for single rocker applications. The thinnest of the dogleg heads are also the rarest 3196291 - c
Thanks!

Note to mods, feel free to move this to whatever section that may be more appropriate.

:idea:

401 Pacer

What in the name of fornication does :idea: mean? :hathat4: :!:

401 Pacer

1980_Cj7 wrote
Finally, a 401 Pacer. I luv it!!!

Sorry, can't help you much on your questions though.

Gonna spank me sum Chebbies! :whipitgood: :youbutthead:

jeepsr4ever

:idea: Just means look at the red areas you will see the replies I had made Yes please continue to spank chebbys :sa:

401 Pacer

jeepsr4ever wrote
:idea: Just means look at the red areas you will see the replies I had made

Yes please continue to spank chebbys :sa:

Ah! Sorry, I'm toopid :oops: :silly:

So, are there any differences of consequence in the block castings? In Mopar-land, the newer the block (more recent casting) the more core shift they exhibit. Am speaking of big blocks in particular....there's even a Julian calender of sorts which indicates this.

Reason I be askin is on accounta the 'fact' that AMC blocks shouldn't be bored over 20....only reason I see for that would be core shift or thin walls (most likely the former). I realize that lots of peepull have bored far more than that, but want to find out how much real world fudge factor there actually is.

Thanks!
PS How necessary is it to install a cam anti-walk plate? I've seen several versions on this here internet, but am wondering if it's so much magic beans or if it's really needed. Perhaps only on hi-po applications?

jeepsr4ever

Dont believe factory TSMs reguarding block bores and oil pressures. Alot of blocks can go way over .060. For instance lots of 390 and 401 blocks can go to 4.25 without block fill (thats .085 over bore). Early 360 blocks can go to 4.165 (Stock 401 bore) and most 304 blocks can go .130 over. Clinder readings from a ultrasonic probe will tell the true story. As far as anti walk systems go they arent needed for anything other than full roller valvetrain (cam/lifters). Hydraulic/mechanical/solid all keep the camshaft in place and suck the large timing gear into the block. When the cam wears out then you get a little bit of walk however the timing cover has a small ridge on it to prevent alot of cam walk.

401 Pacer

Thanks, that's just the kind of info I was looking for. I have access to a sonic doo-hicky so after I hot tank these blocks I'll go a-sonicing.

Any input on those special sauce Torque-Plus metal mesh intake gaskets? Me be thinkin that IF they work, carbonated engines would see the most benefit.

jeepsr4ever

Their are two important things to think about when messing with ports. First off the intake ports must have a certain amount of turbulence but not too much and second is that in most motors any obstruction to the port will cause a power loss. That being said a screen in the intake is a obstruction and without a case by case flowbench proven data sheet I would stay away from them. Intakes runners can be too turbulent for higher rpm and you want that massive wild turbulence to happen after the gases pass the valve :wink: They *may help in lower rpms for gas mileage but for performance I would say no.

401 Pacer

Gotcha about the restriction, but if I understand the theory behind the theory on these gaskets is that the fuel droplets are supposedly split asunder into teeny tinyer driplets :-) That's why I said that this would probably work better on an engine with a carb...injector spray patterns being so fine to begin with, there's not much more that can be done short of changing the physical state of the fuel from a liquid to a gas.

jeepsr4ever

Right however you are also creating turbulence before the valve. Whether or not this will change your efficiency at higher rpms is unknown to me personally but to add a mass in the intake and then say it helps even though its restrictive doesnt sound right to me. I may be wrong about this as I only know a little about a little but if they were soo good then they would more popular. I have seen these gaskets come and go twice in the afermarket over the last 15 years.

401 Pacer

Oh ye of little faith! I'll take "Magic Beans for $1000" Alex :?