how to get 400+ hp out of my stock 72 340????????????

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340plot

340plot

the bushy bush
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ok, maybe all you gear heads can point me in the right direction.
i am taking a fellow members' advice and keeping the 72 340 that is in my 70 34 4 speed car. i am looking to push about 400 hp out of her.
what would be my best options to do? i really do not want to stroke it.

if you could answer these question would be great........... i want a very lopey cam also

1) what manifold?
2) CAN I KEEP THE STOCK MAIFOLDS, AND JUST HAVE MY PORTER PORT THEM OUT?
3) what cam
4)what pistons?
5) can i swap out the pistons with the engine in the car?
6)do i use my manual fuel pump or do i swap to my holley blue with a regulator?
7)can i still run 93 octane?
8) can i keep manual water pump or should i get electric?
( should i go with eddy's? or stay with the j-heads and have them ported and polished?
9) can i stay with the points distributer, or should i go with msd 6al?

i am sure i will have more questions, but that is it for now. if you see something that i am looking at wrong, please point me in the right direction. thanks in advance
 
340plot said:
ok, maybe all you gear heads can point me in the right direction.
i am taking a fellow members' advice and keeping the 72 340 that is in my 70 34 4 speed car. i am looking to push about 400 hp out of her.
what would be my best options to do? i really do not want to stroke it.

if you could answer these question would be great........... i want a very lopey cam also

1) what manifold?
2) CAN I KEEP THE STOCK MAIFOLDS, AND JUST HAVE MY PORTER PORT THEM OUT?
3) what cam
4)what pistons?
5) can i swap out the pistons with the engine in the car?
6)do i use my manual fuel pump or do i swap to my holley blue with a regulator?
7)can i still run 93 octane?
8) can i keep manual water pump or should i get electric?
( should i go with eddy's? or stay with the j-heads and have them ported and polished?
9) can i stay with the points distributer, or should i go with msd 6al?

i am sure i will have more questions, but that is it for now. if you see something that i am looking at wrong, please point me in the right direction. thanks in advance
Click to expand...

1. Intake eddy air gap....exhaust headers...
2. pretty hard to get to 400 hp with stock exhaust manifolds..
3.
4. kb243
5.yes...but the block will probably need to be honed for new rings at least...
6. fuel pump....depends on what you to do...
7. depends on compression, camshaft...cylinder heads
8. if i was driving it daily..i would use stock water pump...race car..convert to electric pump
9. distributor...get a electronic ignition...

you really need to decide on what you are going to do...as with a limited budget you dont want to have do overs...and you want to get the bigest bang for your buck...
 
I would get the Carter High Volume mechanical pump. I have one on my stroker and it has no trouble keeping up.

Put the KB pistons in like above and get it rebalanced. That is the most important thing you should do. The stock '72 340 pistons are very very very HEAVY and have a short "compression height" which puts them lower in the bore and reduces compression. Put the good light weight pistons in there.

Here is a good article:

http://www.compcams.com/Community/Articles/Details.asp?ID=-738676943

Lot of good info in this thread:

http://www.forabodiesonly.com/mopar/showthread.php?t=102257

Water pump: I run a mechanical Flowkooler on mine with the Mopar Performance Viscous Fan Package and a 180 degree Mr Gasket high flow thermostat. Works great.

http://www.flowkoolerwaterpumps.com/
 
as with any engine..cylinder heads are going to be the key to get 400 hp...
 
Someone on a different site told me a while back (he owned a port shop), nooo polishing, unless your gonna be running 7500-8000rpm+. It's mainly used for the little Chinese cars running around.
Smooth surfaces will cause the mixture molecules to stick to the walls of the ports. But If I remember right, a good set of eddy heads is comparable to a properly ported set of J heads.
If money is not an issue, get the eddys.

And I hope I could talk you into going with a Mallory Hyfire 6AL instead of the MSD. The MSD ignitions are known for failure imo, plus the Mallory is more efficient, costs less, and is digital instead of analog.
 
340plot said:
ok, maybe all you gear heads can point me in the right direction.
i am taking a fellow members' advice and keeping the 72 340 that is in my 70 34 4 speed car. i am looking to push about 400 hp out of her.
what would be my best options to do? i really do not want to stroke it.

if you could answer these question would be great........... i want a very lopey cam also
Click to expand...

1) what manifold?
Click to expand...
Edelbrock RPM/Air-Gap

2) CAN I KEEP THE STOCK MAIFOLDS, AND JUST HAVE MY PORTER PORT THEM OUT?
Click to expand...

Well, yes you can, but, the engine requirments would push the build and parts and design of the engine upwards to equal a 470HP or better build since you want to exhaul through a small twizzler straw.

Save the money up for Doug's or tti headers and have a better running engine at a much cheaper cost while driving up efficiency of the parts used.

STOP WITH THE EXHAUST MANIFOLDS ALLREADY!

3) what cam
Click to expand...

A cam as little as 230@ .050 will do the trick easy. A smaller cam requires a better head. Crap flowing heads require more cam and other stuff.

4)what pistons?
Click to expand...
Anytihng that gives you a 9.5-1 ratio with iron heads, 1 pt. more with aluminum.

5) can i swap out the pistons with the engine in the car?
Click to expand...
It is possible if you are double jointed in the arms, spine and neck. Double jointed shoulders would help as well.

Take the danm engine out and build it right!


6)do i use my manual fuel pump or do i swap to my holley blue with a regulator?
Click to expand...
A simple Carter hi vol. pump will do without a regulator

7)can i still run 93 octane?
Click to expand...
Yes

8) can i keep manual water pump or should i get electric?
Click to expand...
A MP hi performance water pump will do fine. Couple the water pump with the MP Viscous fan, new rad, fan shroud and fresh distilled water and anti frezze. I like Peak. Same as Chrysler anti frezee

8A
( should i go with eddy's? or stay with the j-heads and have them ported and polished?
Click to expand...
It's a catch 22


9) can i stay with the points distributer, or should i go with msd 6al?
Click to expand...
You could, but why? A simple MP distributor triggered by a Chrome box or MSD will do great.

i am sure i will have more questions, but that is it for now. if you see something that i am looking at wrong, please point me in the right direction. thanks in advance
Click to expand...

OH! YEA! You need to read a few books on engines before you do anything. OMG! Read dear sir, read!
 
In an over simplification of things and for surely opening up a can-o-worms as to the choice in cams.....

Edelbrock did there "Power Package" in order to sell a system capable of the power they listed for it. The Small block Chrysler package was done on a 340 and clocked in @ 417 HP. A cam change would suite you since there cam is a mello one. A simple centerline change would have it chop like an axe. Power would remain very much the same except peak power would likely be inched up some.

You need to build a zero deck piston height engine and use all the Edelbrock parts minus athere cam. Subout a cam of similar specs or greater and a centerline of 110 or 108. IMO, use the tti headers for best results.

NOW! Are you going to keep cresating redunant threads on the same idea of a topic? Ha ha ha ha ha :toothy10:

By the way, your getting very good acvice here from others.
 
well, i wanted to ask 5 or 6 times before i went and ordered stuff once.lol thanks rumble............. lmao
so, it is time to order, pistons, rings, gasket set.........................
what company makes the best gasket set????????????
maybe i will list some of this stuff in the wanted, so i do not have to buy a new intake?. yea, nay?
who has those kb pistons?
 
Ummmmm, I'm gonna PM you in a min. or so, stand by would ya?
 
I have to ask do you really want that much power?,are you going to race the car at all?,if you were happy with the way a stock 71 340 ran than you dont even need to pull this engine to get that kind of performance.If your looking for a really strong-fry the tires street machine than a cam,manifold and some head work would do the trick.You dont need alot of compression or headers with the right cam/good heads to make power enough to have a blast and even run in the mid to lower 13s with traction-which is a pretty quick street car.I say this not to question you or make your head spin around but once you get into the the bottom end your going to spend some bucks and a small budget wont cut it,even if all it needs is a hone by the time you buy pistons,rings,bearings and pay for the hone,crank polish,balancing ect. your about a grand already and you haven even bought a cam let alone the top end,headers ect.Just my opinion but if cash is a concern I would do some basic upgrades and enjoy it until I could build another engine from scratch.
 
You need to have the pistons replaced with performance ones (I'd use KB 243s). Have the block square decked to 9.580. have the rods redone w/ARP bolts, turn the crank, internally balance it. Have the heads done with 2.02/1.65 valves witha 5 angle valve job and a gasket match. No porting needed. Trim gasket surfaces for 70cc chambers and to account for the block decking. Stock intake and exhaust manifolding can be used but I'd run an Edelbrock Thunder AVS instead of the factory carb and get a real ignition. Stick in an XE268H cam, tune it, and you're at 400hp.
 
lead69 said:
I have to ask do you really want that much power?,are you going to race the car at all?,if you were happy with the way a stock 71 340 ran than you dont even need to pull this engine to get that kind of performance.If your looking for a really strong-fry the tires street machine than a cam,manifold and some head work would do the trick.You dont need alot of compression or headers with the right cam/good heads to make power enough to have a blast and even run in the mid to lower 13s with traction-which is a pretty quick street car.I say this not to question you or make your head spin around but once you get into the the bottom end your going to spend some bucks and a small budget wont cut it,even if all it needs is a hone by the time you buy pistons,rings,bearings and pay for the hone,crank polish,balancing ect. your about a grand already and you haven even bought a cam let alone the top end,headers ect.Just my opinion but if cash is a concern I would do some basic upgrades and enjoy it until I could build another engine from scratch.
Click to expand...

If the motor has good compression and don't us oil............this^^^^^Is a sound idea!
 
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