Help Choosing a Cam/Converter- 9:1(ish) Stock Stroke 400

[JG71B]

This will be in a 71 B body, 3.55's. Running headers also, pretty much stock 452 heads with a little clean up, gasket match (not ported), basic 3 angle and a Weiand Action Plus intake. Ill be running power brakes. This will be mostly a driver, occasional track time once maybe twice a month during the summer. Been out of the game for a minute so, I'm sure a lot's changed since my last build. Appreciate any input

 

[qkcuda]

I am part way through a similar build for my Charger. I chose the smaller Summit cam 214/224 duration. Hopefully I will have dyno results within the next few weeks.

 

[451Mopar]

383 or 440?
Converters have come a long way. A "tight" high stall converter does not have to feel loose in normal driving, but won't hit as hard at the track.
Speak with the companies that make custom torque converters and discuss your build with them to see what they offer.
I'm currently running an custom 9" Ultimate converter in the '71 Charger. It was a bit pricy, but works nicely on the street.
Custom Torque Converters for Drag Racing - Ultimate Converter Concepts

 

[JG71B]

I am part way through a similar build for my Charger. I chose the smaller Summit cam 214/224 duration. Hopefully I will have dyno results within the next few weeks.

I been following. I'll keep an eye out for that. I used that cam about 15yrs ago with good results in a 440

 

[JG71B]

383 or 440?
Converters have come a long way. A "tight" high stall converter does not have to feel loose in normal driving, but won't hit as hard at the track.
Speak with the companies that make custom torque converters and discuss your build with them to see what they offer.
I'm currently running an custom 9" Ultimate converter in the '71 Charger. It was a bit pricy, but works nicely on the street.
Custom Torque Converters for Drag Racing - Ultimate Converter Concepts

Awesome thanks! This is a 400 stock stroke. POSSIBLY may go with a 440 crank but if I do it will be the 400 rods. Most would suggest 440 rods but, I know of a 400 set up like that and the torque is ridiculous. For now stock stroke 400

 

[Curiousyellow71]

You would not regret the 440 crank. You would have to cut a 440s counterbalances with the shorter 400 rods or the pistons hit. Not every shop does that..but it can be done in a lathe. If you don't cut the counterbalances w a 440 rod, then more time has to be spent grinding on the block so the crank can turn, the exception being some of the early 230 blocks, they seem to have more clearance. Cutting the mains to b takes a machine shop a bit longer but usually isn't real expensive. Aftermarket stroker cranks is what most now do.

I would suggest having the valve guides cut for viton seals and get new valve springs that match the new cam. It's a simple procedure, you can even buy a cutter and do it yourself if you want.
Several convertor companies have stepped up their game doing tight convertors. IMHO a 9 1/2" is a great size for the street..we now have used 5 of them. They have great street performance because they are tight, but leave the starting line more like a racecar, PTC is probably the most reasonable priced custom brand, we also have a ultimate by Lenny, FTI and a dynamic. Several companies market their convertors as 9"..but when you measure they are actually 9 1/2"???marketing I guess.
For 3.55s a hughes 24-2500 convertor is OK for a budget built, but their price has almost doubled? They are a looser built convertor so 2500 is about all I would want with your combo. The other entry level over the counter brands I would stay away from.

I would nail down your plan for the engine internals before you buy a cam. I would try to buy old stock lifters if you can find them.

 

[JG71B]

You would not regret the 440 crank. You would have to cut a 440s counterbalances with the shorter 400 rods or the pistons hit. Not every shop does that..but it can be done in a lathe. If you don't cut the counterbalances w a 440 rod, then more time has to be spent grinding on the block so the crank can turn, the exception being some of the early 230 blocks, they seem to have more clearance. Cutting the mains to b takes a machine shop bit longer but usually isn't real expensive. Aftermarket stroker cranks is what most now do.

I would suggest having the valve guides cut for viton seals and get new valve springs that match the new cam. It's a simple procedure, you can even buy a cutter and do it yourself if you want.
Several convertor companies have stepped up their game doing tight convertors. IMHO a 9 1/2" is a great size for the street..we now have used 5 of them. They have great street performance because they are tight, but leave the starting line more like a racecar, PTC is probably the most reasonable priced custom brand, we also have a ultimate, FTI and a dynamic. Several companies market their convertors as 9"..but when you measure they are actually 9 1/2"???marketing I guess.
For 3.55s a hughes 24-2500 convertor is OK for a budget built. They are a looser built convertor so 2500 is about all I would want with your combo. The other entry level over the counter brands I would stay away from.

I would nail down your plan for the engine internals before you buy a cam. I would try to buy old stock lifters if you can find them.

Yeah if I did the 440 crank, I'll just hit 440Source up on that. For sure on the vitons when the time comes. As far as converters, I'll make some calls to those vendors mentioned. But Im probably leaning to just a basic rebuild and just bumping compression up. Appreciate it

 

[6PKRTSE]

383 or 440?
Converters have come a long way. A "tight" high stall converter does not have to feel loose in normal driving, but won't hit as hard at the track.
Speak with the companies that make custom torque converters and discuss your build with them to see what they offer.
I'm currently running an custom 9" Ultimate converter in the '71 Charger. It was a bit pricy, but works nicely on the street.
Custom Torque Converters for Drag Racing - Ultimate Converter Concepts

Agreed. I run a 9" 5600 PTC nitrous converter in my Challenger on the street. It acts as normal as my more stock to stock-ish cars. I have 3 cars with different size/stall PTC converters and happy with how they all function. One car has close to 60,000 on it with the same trans & converter.

 

[PRHeads]

I wouldn’t finalize the cam choice until you’re pretty well sure of what the rest of the short block/combo will consist of.
If……. It ends up at very close to, or slightly over 9:1 CR, then I’d use a Comp XE268.
If you end up closer to 8-8.5, I’d step down one size to the XE262.

 

[qkcuda]

I would use a stock 340/383 converter if I could find a good used one. I picked up a factory 400 11 inch core and I am planning on having it rebuilt locally into a 2500 stall.

 

[JG71B]

I wouldn’t finalize the cam choice until you’re pretty well sure of what the rest of the short block/combo will consist of.
If……. It ends up at very close to, or slightly over 9:1 CR, then I’d use a Comp XE268.
If you end up closer to 8-8.5, I’d step down one size to the XE262.

I plan on it being between 8.8 and 9.2:1 max with the KB pistons I plan to use, variables being how much to deck the block and headgaskets etc

 

[451Mopar]

Awesome thanks! This is a 400 stock stroke. POSSIBLY may go with a 440 crank but if I do it will be the 400 rods. Most would suggest 440 rods but, I know of a 400 set up like that and the torque is ridiculous. For now stock stroke 400

One of the reasons the 451 stroker was popular using the 440 crank and 440 rods is the pistons are almost 1/2 the weight which is good for performance and durability.
It was also pretty affordable. Later when the inexpensive stroker kits arrived, they were a very good value. Inflation has really upped the cost of the stroker kits now, but I like the rods with the 7/16" ARP2000 screws.
My 451 used stock 440 rods with ARP bolts, and they never gave me a problem. I do think the stock rods and 3/8" rod bolts would be the weak link of the short block.

 

[lewtot184]

i would consider what your doing as a near stock plus build. i've used the summit 6400 in a 9:1 383 build and thought it was a good driver cam. i've used the comp cams magnum replacement (21-305-4) in 440's before. this cam is a little gentler than the xe268. for a more performance build i used a crower 201hj in a 383 4spd. it was the best general purpose cam i used in that 383. it's rated at 280/.480 it would like at least 9:1 compression. that lobe isn't available from crower anymore (it's actually an older crane lobe) but howards has that lobe in their catalog; it's 1hf227320. one thing for sure is don't over cam!

 

[PRHeads]

I just ran the numbers………Looks like the 9:1 target will be easy enough to reach.

With no milling and 88cc heads, and using a .040 gasket, you’ll start out at about 8.3:1.
Then you need to lose 9-10cc’s somewhere, which brings it right into the 9:1 range.

 

[JG71B]

I just ran the numbers………Looks like the 9:1 target will be easy enough to reach.

With no milling and 88cc heads, and using a .040 gasket, you’ll start out at about 8.3:1.
Then you need to lose 9-10cc’s somewhere, which brings it right into the 9:1 range.

That seems achievable with a steel shim!?! gasket. My next question is if I should have the block squared. I don't want to go too far on anything if not necessary. I'd like to keep it at 9:1. The heads will lose enough to make square at most. At this point I'm still on the fence on the rotating assembly. I may just use the factory bottom end to keep it somewhat on the cheap. I have a good steel 383 crank and balancer on hand to be reconditioned. I also have another 400 on hand to stroke down the road. Basically, the cheaper I keep it the sooner it will come together

 

[451Mopar]

Check that the block and heads are flat for gasket sealing. If it is a stock block, most likely it won't be perfectly "square", as in same height front to back and side to side.
If you mean cutting the heads or block for compression, that can be done. If doing that, need to also cut the intake side of the heads so the intake fits correctly.

 

[JG71B]

Check that the block and heads are flat for gasket sealing. If it is a stock block, most likely it won't be perfectly "square", as in same height front to back and side to side.
If you mean cutting the heads or block for compression, that can be done. If doing that, need to also cut the intake side of the heads so the intake fits correctly.

Yup! But, more just so that they are flat/square more so to gain compression. I don't wanna be shimming rockers and all that also that's what the KB's are for lol. The heads are actually on a running motor in my car now

 

[451Mopar]

Which KB pistons? Flat top?
The quench dome pistons are a different story. Not even sure they have them for that engine?

 

[JG71B]

Which KB pistons? Flat top?
The quench dome pistons are a different story. Not even sure they have them for that engine?

I'll have to look again. I may have confused them with the 3.75 stroke pistons.

 

[qkcuda]

Theoretically the KB240 pistons sit .025 in the hole. They milled a little less than that off my block to get it to zero deck. My numbers with 89cc heads and a .041 gasket are just a hair under 8.7:1. I substituted a .020 gasket and it came in just over 9:1.