Allen
I just got this intake, and found out it is not good for daily driving(sacrifices low end). A friend of mine suggested a plenum divider to put in there to help with the low end some. Does that need to be notched at the bottom also? Any opinions welcome!
Thanks!
Allen
71_TA_Javelin
If you have room... Use a 2" spacer that is a four hole patern. You may need to use an after market air cleaner for clearance. I have been able to use the combo on a 73 304 with a 650cfm Holley with a little squirter mod to help on full throtle bogs. Everyone told me it was too much for a stock 304.
Allen
Oops, I forgot to say this was on a 360 on a full size jeep. So do I need to run the spacer and a divider? The manifold did come off a 304 but no mods were done to it. A lot of what Ive read has said that you couldnt run it on a 304. Good job on proving them wrong!
71_TA_Javelin
No divider needed if using a spacer that has 4 ports not an open port. Plus you can use a larger carb with the setup. Torkers need a larger carb any way but it all comes down to floor depth... look down into any intake. If the floor is deep then you can get away with using a large carb. By using a 2" spacer you are making the floor a little deeper. My method will add torque by allowing more direct draw from each venturi by increasing volocity. By having the port one big pit to dump gas in, only allows for high RMP to compensate for the lack of volocity. Basically your tuning your Torker down to streetable standards. I looked around and found a few heat resistant spacers for around $15.00 including the longer studs and nuts. Some aluminum ones go around $40.00. The nicest thing it keeps your carb cool. You may find some Mr. Gasket adjustable spacers (sandwitch style and heat resistant too!) for a good price too. I used the Mr. G on the 304 back when I had it... since I was playing around with an Offy equaflow 360 spread bore version (A$$ kicker for the 304/360) 25mpg hwy and awsome responce when dumping fuel. Funny thing can'f find them anywhere anymore.
Holeshot
"sacrifices low end"???? Are you driving a dyno around??? I hardly think you will notice 20 HP missing at 3000 RPM, but I'd sure feel it missing at 6000!!!
SwampRat
Not only will losing horsepower at a mid-range RPM be very noticeable because it will make the engine work harder to re-accelerate after a shift, but losing low speed performance is magnified when the engine is under part-throttle conditions.
Also, to previous posters. A dual plane intake needs more carb CFM for performance since this way the piston only has access to half the carb, not vice versa. Putting a single plane intake on a engine with a larger carb than a dual plane would be a way to increase the decrease of low speed performance (if that makes any sense). A four hole spacer should help, it increases venturi length, and helps fuel atomization, while adding "effective" CFM flow to the carb, but it would probably not be as noticeable a difference as a divider. But with a divider your playing a guessing game on what is gonna work and what is gonna cost you, the best bet is just to get a edelbrock performer RPM or a R4B intake manifold.
Holeshot
yeah - lose 20 down low or gain 30 up high, your choice. Have it your way, it's your ride.
SwampRat
You have to think of the time the engine spends "up high" and how useful it gonna be for the vehicles gearing/setup. If a engine has tall gears and a auto with a tight converter adding all that "up high" won't do a bit of good after it bogs down after a shift, not to mention making it a bitch to drive on the street.
I just bother you because I want people getting the right information, your too old school, and don't look at these things closely enough, that is all. Nothing against your person, just trying to make you think a little more.
jeepsr4ever
You dont want a torker on a AMC V8 unless your going for mid to high range rpms. 4000-7500rpms is the range the torker works well in. It will not give you very good low end if your running this in a Jeep type vehicle or a daily driver. You can have alot of fun with it in a daily driver if you are built to handle the R's though :!:
Allen
Well I got her all installed, and put a Holley 600 on top of it. STILL messing with the holley(idleing probs etc). No vac leaks. I installed a spacer that has a removable middle where you can tun open or 4 hole. I tried the 4 hole and when I started it, it immediately went to 1900 rpm and I couldnt get it to idle down. I didnt try the mixture screws now that I think about it, was more shocked at the engine revving so high and now being able to control it. I put in the open middle piece and when it started, it immediately went to 750 rpm(had the curb idle adjusted all the way out).
It doesnt like the cold, and now it will fall flat when cold as I hit the gas a lil, but I can adjust that out. I think the carb had nozzle drip and it drains out my primary bowl onto the butterflies. It will idle great once its warmed up. I might have it just a lil rich on the mixture. It has a lot more pep when it was leaner. No matter what tho, when I get it out of the drive and hit the gas, it gets up and flat out moves!
Right now the truck has 4.10's and a th400 auto. Its normal for me to run 3000-4000 rpm down the highway. The combo works great, I get to 70 mph almost like a normal vehicle now! :) Question is, with this manifold does it need to idle higher than normal?
SwampRat
A single plane manifold will lean a engine out, when you used your open spacer and added plenum volume as well you had the same effect, you tamed your horridly rich idle by dampening the induction pulse that brings in the fuel and thus fuel atomization suffered along with the effective amount of fuel used in the engine.
A single plane manifold also makes less manifold vacuum at idle than a dual plane, also needing a richening of the idle mixture and a increase in idle RPM.
This is working on the same theory of a large camshaft needing a higher idle RPM (as many can see this concept easier), it all involves adversely effecting the incoming fuel quaity at idle, if by added exhaust heat and contaminants in the combustion at idle due to overlap, or dampening of induction pulses the fuel atomization overall is worse.
Holeshot
Like I said, give up a little low or gain a bunch high.
Giving away a few HP or ft/lbs. of torque is quite insignificant when you have a stout 401 with 419 ft/lbs @ 2000 RPM & over 500 ft/lbs. from 3500 to 5500, and over 500 HP from 5000 to 7500 RPM, now does it?
If you were building a 401 just for torque, over 600 ft/lbs is not hard to get if you don't mind settling for a peak of 320 HP @ 4000 and rapidly dropping to 149 HP @ 6000, right SMACK where the head design wants to work!!! Then everybody else will want (and be able) to get in front of you early so they aren't stuck with you plugging up the trail while you smell the flowers and see the sights.
I think ya need to start with the head, since it truly is "cast in stone" (iron).
Shouldn't you build your engine around whatever the head will flow???
Since the head (with common AMC mods) wants to push over 250 CFM, and will flow well enough to breath to 7000~7500, why would you want to choke that down with a little carb, little intake, or little exhaust?
If you want to run slow, get a '68~69 390 with square ports and build for a 5000~5500 redline, which is about where those heads poop out.
Please don't get me wrong, I know that some people do want to go slow (trail riding), that is perfectly fine with me, I've done it on motorcycles for years, and it is fun, especially if it's a quiet machine.
So, again I say, to each his own (or zone).
