The pistons are the flat top with relief.

 

I stand by my original recommendation except you will need to step the cam up a notch because of the flat tops and go with a 2500 stall torque convertor because of your gearing and specs.(I would guess about 400HP)
http://www.summitracing.com/parts/HRS-110245-14/
Or you can change to 75 CC heads and keep the original cam recommendation but it will cost you power. ( about 350 HP maybe a little more.)

 

thanks for the help on coming up with a configuration that comes inline with what I would like to do power wise. Ill look at the list again. So the depth of the pistons are high enough in the hole, that the thicker gasket will be sufficient?

In this scenario, how much bleedoff of power would be attributed to the TH400? any diff in 2000r4 ?

 

The pistons are down in the hole .025 (+ or -) That coupled with the gasket I recommended gives you .038 to .042 quench. Perfect. The 200R4 saps less power than the TH400. A 700R4 would be a better match for your rear gearing but install is more difficult. A 200R4 with a 2500 stall convertor would probably work good and it is a closer ratio on the upshift, important with 3.08 gears. The convertor is a torque multiplier so it "feels" different than the actual final drive gear but 10 to 1 first gear final drive is usually considered optimal for performance. There is a lockup convertor available also. You really don't need an overdrive with your 3.08 rear gearing so I would look at the right stall lockup convertor for your TH400. There are others on the forum more knowledgable than me about auto trans conversions and torque convertor selection. Might want to start a new thread on this question.

Gearing:
TH350 2.52:1 1.52:1 1:1 N/A 7.76 to 1 first gear final drive
TH400 2.48:1 1.48:1 1:1 N/A 7.63 to 1 first gear final drive
700R4 3.06:1 1.63:1 1:1 -0.70:1 9.42 to 1 first gear final drive
2004R 2.74:1 1.57:1 1:1 -0.67:1 8.43 to 1 first gear final drive

 

Thanks again, much appreciated.

 

The Dart heads that you originally recommended have a 64cc combustion chamber. These heads:

http://www.jegs.com/i/Dart/301/12722...ductId=1691309

are the same heads with a 72cc combustion chamber, for the same price. Would these be a good head for the OP to use if he didn't want to use a 2500 rpm stall converter and bigger cam?


Scott

 

I also forgot to mention, that the intake manifold was aready a Performer, so looks like that part is one I wont have to worry as much about.

 

Yes. I recommended a 75CC head to get similar compression but from what I can tell the Flat top pistons are about a -5 cc and the L48 is about 13cc. That is 8 cc different. The dart heads are 64cc or 72 cc or 8cc different. With aluminum heads, flat tops and good quench I would bet the original roller I posted will work fine. Hey, there are hundreds of combinations that will work to do what the OP wants but when you take budget, gearing, trans, car weight, and bottom end limitations into consideration it narrows the field some.

 

when I look at heads and cams, what should I be looking for to tell they will or will not work together? i just want to try to compare different combinations and I am not sure how to do that.

i think i understand quench to be the about of space between the top of the piston on the bottom of the heads which includes gasket.

But I dont know how the CC of the head + the quence etc gets to a general HP rating, or other items that need to be concidered into it.

 

Having the proper quench is about detonation resistance, mostly, although there are several other minor benefits. The thing here is that if you decrease the thickness of the gasket to get to the proper quench, it increases the compression ratio. To compensate, you use a head with a larger combustion chamber to bring the compression ratio down within reasonable limits.

As far as how to pick heads and cam, that's a little tougher for me to answer. All I really know is that you try to pick components that are optimized to work well in the same rpm range. What I have done is pretty much to learn enough about the subject myself to be able to tell who knows what they are talking about, and who is just blowing smoke. Then I take the advice of someone who I think knows what they are talking about. Hope that help, see ya,


Scott

 

There is a lot involved. Head flow will tell you maximum possible hp. That said a 220cc intake port don't work on a 350 and a 170cc port don't work well on a 434. A 350 might be best suited with 170cc intake ports if your looking for low rpm, high torque towing or a 200cc port if it is pulling 7500 RPM shifts in a light car with optimal gearing. A 200 duration @ .050 cam lift lift and 8 to 1 compression might be ok for a tow truck and a 300 duration @ .050 on a 13.5 to 1 solid roller 8000 RPM engine. A numerically lower overall gear ratio needs a lower peak torque and a lower operating range cam. A numerically higher overall gear ratio can use a higher peak torque. Cam duration determines operating range. Lift at the valve can go up with duration or a roller upgrade. Another variable is LSA which generally runs between 106 and 114 and will affect idle quality, fuel mileage, width of torque band and a variety of other engine characteristics. Then there is dynamic compression which will give you a guideline on the ability to run pump gas. This is determined by static compression, rod length and intake valve closing point. An aluminum head will take a higher DCR than an iron head without detonation issues which allows higher compression and/or a smaller duration cam. Weight of car, rear end and trans gearing, RPM capacity of the bottom end and intended use all contribute to determining what type of engine build specs you want. The engine build needs to be matched to all other internal engine components taking all the above into account. You can buy AFR CNC race heads with a 180 port that flow close to 300 cfm or an as cast 180 cc from a variety of manufacturers that flow 230 to 250 cfm. Price will be different. The higher HP you build the more expensive the build and the more critical proper gearing for best use of the powerband is. When you hit a certain point higher power handling drivetrain upgrades are required. Experience is probably the best teacher for the ability to design a build that is well matched internally and meets the needs of the driver and the fixed parameters that are existing in the car.

 

See what I mean?


Scott

 

Yeah I know it is an art and experience is the key to getting the right combination.

63, i know you were staying within the 2K budget etc when you put together the combination of heads and cam etc. If I could increase the budget but do no tranny changes, and leave my rear end as is and stay under the factory hood safely.

What other combinations would work, for say either a mid level entry point or an entry point right just before needing to modify the drivetrain etc.

I like to compare price levels as "proven" quality parts are added. Like edelbrock, or vortec heads etc.

I hope that makes sense. seems like my price level I had set was more entry level. I had set that because I thought I may switchout the tranny, but if I keep it, and use that money then I have more to play with.

Thanks, and hopefully I am not being a pain in your a$$

 

I guess there is something else I did not think about will the type of pump gas that is needed (premium over reg unleaded)? the 96 we had required the premium for example.

 

Well matched components in both the engine and the total engine build matching the cars fixed parameters and intended use is the key to a successful build that you will be happy with long term.
Intake
Your performer is not the best performance intake but for your application is very good. The operating range is idle to 5500 RPM which is in line with your bottom end capabilities and you want bottom end and midrange power because of your gearing and trans. It is a dual plane which is also best for bottom end and midrange torque. It fits under your hood and has already been setup to work on your car with your carb and accessories.

Heads
http://www.users.interport.net/s/r/srweiss/tablehdc.htm
This is a good place to start for comparing different heads. For your performance level I would look at 180 cc intake port sizes. That also matches your performer intake port size well. If budget is going up the best performance head available for any sub 6000 rpm 350 application would be AFR 180 for about $1400. They will make the most power across the board for a 180cc head and will handle almost any future upgrade you are willing to throw at it yet work well with almost stock build specs. Aluminum heads will allow more compression with a given camshaft which gets you more power and allows a cam duration that fits your gearing without sacrificing compression.

Quench
.040 is considered best in a street application. You get better "squish", better flame travel, more complete combustion, better efficiency, better detonation resistance. Flat top pistons help optimize the benefits of good quench.

Camshaft
You want a hydraulic cam for your application. Solid lifter cams are great but generally used in high RPM applications. Your stock bottom end limits you to under 6000 RPM operation so hydraulic is the way to go for durability and ease of maintainance. Your two choices in a hydraulic are flat tappet or retro roller. Your engine came with a flat tappet cam. Retro roller will allow more lift at a given duration. A roller cam allows the valve to open and close faster, giving to valve more time filling the chamber. see here:
http://www.harveycrane.com/duration.htm
Almost all modern engines use a roller cam and have since to late 80's.

Lift: best performance from the head is cam lobe lift numbers that take advantage of the flow the heads will allow. If a head flow stops at .500 valve lift there is little to be gained lifting to .600 as long as the duration remains unchanged.
Duration @ .050 is what you will use to determine a cams operating RPM range. There is no sense putting a cam in your car that pulls to 6500 RPM when your other components limt you to 5500 RPM.

LSA Is the lobe separation angle. For an automatic heavy car with high gearing I would look at a 112 or thereabouts LSA.

This will help explain some of the things you need to know to compare cams.
http://www.popularhotrodding.com/eng...s/viewall.html

Dynamic compression. This is a guide to determine if the cam you decide on will actually work with the static compression you are running using pump fuel. Read more here:
http://www.empirenet.com/pkelley2/DynamicCR.html
The parts I suggested will allow the use of Premium fuel. Once it is together with a recalibrated timing curve and correct A/F ratio you can try midgrade or regular in it. Some builds, if there is careful attention to detail, good quench, good cooling system, ect will run on less octane than originally calculated. There is no advantage to running higher octane than that needed to avoid detonation. If you have to run premium you have optimized your build

 

I think that will help plus I can compare to the list you gave me originally. Thanks for breaking it down less technical

 

I did some research and talked to trackdogg here in the dallas area for different brands etc. Here is a combination I came up with based on his recommendation as well as the ones from this thread.

Any issues with this combination?
cam - http://www.summitracing.com/parts/LUN-10020LK/
gasket - http://www.summitracing.com/parts/FEL-1094/
intake - http://www.summitracing.com/parts/EDL-27014/
headers - http://www.summitracing.com/parts/AFR-0916/

not sure which other gaskets or which rods, but this is mytake on it based on all the feedback.

 

Awesome Combo........All proven, well matched parts. Duration @ 050 is right wher I was and a hair more lift at .500 and the 180 AFR heads will like it. It would sure like a new convertor. The heads are the best and I really think the AFR 180 eliminators will be a great match for a sub 6000 rpm 350. If you can get sping specs for the cam have the heads setup with the correct beehive spings for your cam. Check the threaded hole in the head for the temp sensor. You might have to drill and tap it for the bigger sender. The new intake will match right up on the ports and setup will probably be exactly as it is now. Be nice if someone did a desktop dyno for you on this. Results might suprise you.

 

I know I need to wait on the thrust button, and rods until I can measure with the new components.

Should/can I use the rockers I have or should they be changed out also? if so is there a style that would work better for this application? I know if I cant get the rod lenghth within a certain range while trying to set them up, diff rockers would be needed.

 

Full roller rockers are nice. That said for an under 6000 RPM engine they are probably not absolutely required. I would go with a good brand, Comp 1.52 to 1 comes to mind, roller tip at a minimum. The cheap full roller rockers have been known to come apart, sending little roller bearings throughout the engine. The factory rockers are not accurate on the ratios and the quality aftermarket rockers are right on. Cloyes has a timing cover with an adjustable thrust button. After everything is assembled you will want to use a pushrod length checker to determine the correct pushrod lengt, then order them.