View Full Version : 340 stroker motor to 410-416ci
I know there is some talk about the small block strokers out there. I am curious about the 4" stroker setup. I have a 340 block that does not need bored out, it measures a perfect 4.040". I want to build the 4" stroker setup on pump gas that will run high 11's and run on the street. My current 340 runs 12.5's shifting at 6,800rpm, using "j" heads that are mildly ported.
Who has actually run one of these? Any real timeslip or dyno pull from one vs a normal small block?
What kind of rpm can you get out of one of these?
Rod angles - I've heard some consern on the rod angle being too severe? Just get better rods?
Any input is greatly appreciated.
10-29-2001, 05:51 PM
just got finished putting in my 408...360 block 30over 4" stroke.
Eagle h-beam rods..studded mains...Ross pistons...Edelbrock heads with moderate port work(mostly in the bowls) 10.25 to1 comp. Comp cams 525 lift / 305 duration..253at .050in.
RPM intake..holley 750dp no choke tower..heddman 1 5/8 heddars..2.5 in tti exhaust...727 3000stall..3.91 gear..275/60/15 bfg drag radials down to 15 psi...72 barracuda all steel street car w/full interior..probably 3400-3500 lbs..mech. carter fuel pump and 92 octane gas.....Hensley motorsports built the motor for me..very impressed with there work and helpfulness....this was the results
The car was driven to the track 1 hour away
1st pass....8.02..1.99 60's...90mph
was a little disapointed but was happy with mph...360 built the same ran 85mph
2nd pass...7.67...1.77 60's 91.2mph
getting much better. still spinning in 1st
3rd pass..7.66 1.76 60's..91.2mph
I have 60'd 1.65 with the old 360
the car has the heavy duty leafs but stock front suspension. going to try an adj. pinion snubber soon.
shifting at 6000...car does have 6al msd...6400 chip....definetly want to keep the motor together..
With the 4" stroke you will not need to buzz the motor to 6800..
what kind of stuff have you done to the 340?
I'm looking to run some 7.40's soon Got lots of tuning...Ran those times with only 35 deg. timing and hadn't played with the jetting at all.
Thanks Brian, That is the kind of information that I'm looking for. My current 340 with 10:1 on 93 octane 38degrees timing with 3800rpm stall runs a best of 1.78 (60ft), 7.99 @ 85.5mph (1/8) and firstname.lastname@example.org, driving it to the track. I go through the traps at aroun 6,400rpm with 28" tires and 4.56 gears.
I'm hoping to make more torque and shift it lower than 7,000 rpm (around 6,200rpm), but I want it to pull to at least 6,500rpm in top gear at the end.
Your combo sounds great. Very impressive. Did you have an engine in it before the stroker?
10-29-2001, 07:25 PM
Brian, with your new motor it will want more jet than your old setup, sounds like you've got a screamer! Hensley built my heads on my .030 340.:)
10-29-2001, 09:50 PM
71 scamp..actually your times are my goal now..I can see 7.5 range potential on a good hooking day and some proper tuning. I want to see what some bigger exhaust (3" to the mufflers..want to leave the 2.5 over the axle though) What do you think about that? I spent about 12 hours grinding and welding up my heddman heddars ports so they would be atleast as big as the ports on the heads... Do you think the motor would like a set of 1 3/4 hedders? What size do you run?
What kind of mph do you have in the eigth?
always want to go just a little faster!!!
10-29-2001, 09:56 PM
for lar... I had a 60 over 360...371 ci...same heads...intake...oilpan(milodon) ...camshaft....
car went 8.02 at about 85.5 mph....1.65 60's...that was with 26" tall nitto drag radials....That was the2nd pass on the car...it just got slower from there but that was a whole fifferent problem...
The carb that I just bolted on really seemed to wake up the new motor... it has had it's choke horn removed and looks just like an HP...It does have some years on it though...a buddy of mine had it from another friend to sell. Think it can be mine for about 150$
I don't think I can beat that price....
Does anybody know anything about the internal balancing of these cast cranks? I know they need to add Malory metal to get it balances, but why? Is the cast crank counterweights too light? Is a cast crank lighter than a forged crank? Do they have to do the same with the forged 3.79" cranks?
I saw that when you buy a kit from Mancini's, they will internally balance it for $350. Is that a good amount to pay, or can it be done cheaper? I'm thinking of buying the parts I need (from different sources - to save $$) and getting it balanced somewhere near where I live.
10-31-2001, 03:48 PM
I really do not think any malory was added to my new crank. If anything the counters were drilled quite a bit. The stroker pistons are considerably lighter due to their short height. My motor was balanced with a notched B&M flexplate. No weights on the converter.
Brain, that means that your engine was Externally balanced. B&M has a flexplate that uses a cut out area instead of adding weight 180 degrees on the other side.
From what I'm told, to Internally balance the engine, heavy "mallory" metal is needed. They drill the counterweight from one side to the other, stick a slug of mallory in, and tack weld it.
Internally balanced motors do NOT need the special flexplate/flywheel or notched balancer (like a cast crank 340 vs a forged crank 340).
11-01-2001, 02:53 AM
A friend built a 360 stroker last year with the Edelbrock heads, 11:1 compression and a solid Mopar Cam (I forgot the grind, but it was fairly big.)
This is in a Challenger and it runs high 11's at 4,500 ft altitude.
Do you know if that is on pump gas? With that altitude and compression ratio, you could run pump gas if the cam is big. I'd like to build mine around 10.6 to 1 with a 250 @ .050 cam on pump gas (93 octane). The altitude around here is mostly 1,500 ft.
What pistons are you running brian? part #? and weight?,LAR I ran a 360 with Edelbrock heads,had 175 cranking psi,on 91 octane,ran 1.89 60 ft and 8.3@86mph with 3.23 gear and 235/60/15 drag radials @ 4600ft.It went a best of 12.58 @109 thru the exhaust.Im currently building a 408,looking for mid 11s in street legal/pump gas trim........PRO...
11-03-2001, 12:14 AM
Brian, I would for sure go with the 1 3/4" headers on a 408 with Edelbrock heads. Hooker Super Comp 5204 is a awsome header for a small block A-body. I run them on my Dart and 71 scamp runs them also. He will also tell you a very nice fitting header.
11-04-2001, 12:59 PM
PRO, the pistons are Ross from Hensley. I'm sorry but not sure of the weight. PN from Hensley...HRE09002.
I'm looking to get the 1 3/4 soon. May be back at the track next weekend for some new times.. Going to do some more tuning.
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