I have a 82 w150 4/4 and a stock slant six Its rebuild time, I want GOOD mileage and the strongest power i can get from 0 to 4000 RPM uno a 225 thumper anyone ever built a big block 225 hehehee

Most power is made through head porting and bigger valves and then make sure you get at least 8.5:1 actual comp (factory rated was 8.4, but more like 7.5 in reality).

Lou

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Home of Slant6-powered fun machines since 1988

The careful selection of a cam, matched to the static compression ratio and intended RPM range will be the key to success.

Spend some time reading and understanding the consept of Dynamic Compression ratio. Do Some Calculations. There are a bunch of calculators out on the web.
Here is a link to a good overview of DCR.
DD

http://www.empirenet.com/pkelley2/DynamicCR.html

Thanks for the input guys But that stuff is way over my head My thinkin was that as old of a engine as the slant is someone has made one allready and could advise me to use certain componets to make my slant a leaning tower of mega torque at lower RPMS with the top end at about 4000 Has no one done this before Ive been lookin for a e mail for doc dodge But its hard to find he seems to be the one who knows the most NO afence to any body and i am greatfull for anyones oppinion THANKS GUYS

Doc = Doctor Dodge = Doug Dutra

OK... so you don't want to do any math...

Take apart your SL6 and measure the head's combustion chamber size in cc's & measure how far down in the cylinder the piston is at TDC.

Rebuild the engine so you have a 50 cc head chamber (mill the head "x" amount) and a -.145 piston to deck height. (mill the block "y" amount)

Buy the special Erson RDP cam # RV10/295 and use it installed at zero to 2 degrees advance.

This combo will produce a 8.8 to 1 static compression ratio and 8.0 DCR.
If you bore-out the engine to 3.460 (.060 oversize) the static compression will be 9.0 and the DCR will be 8.18
DD

Jimmy-

There is no "one engine build fits all" for any motor. Unfortunately, you must do the research and choose the parts that will give you the results you want for your particular motor and application.

I have done some research on building up a slant six for torque and fuel efficiency for my brother's 83 shorty van. This is what I have come up with, but be advised, you might not like this combination.

CAM- Erson RV10 profile. The profile is given in another post on this site, use the search function to find it. Good low RPM torque cam.

VALVES- for a truck or van operating in the below 3000 RPM range, I think stock valves with port work and a three angle valve job are fine.

COMPRESSION- You want to aim for as much dynamic compression as you can get using the fuel grade of your choice. To determine your dynamic compression ratio, you will need to pull the motor apart and take accurate measurements of the combustion chamber, piston deck height, and cylinder bore. You must take these measurements after you have done any overboring in the cylinders and valve unshrouding work in the head. You will also need to select your camshaft and determine the installed centerline of the cam before you can calculate your dynamic compression. You want to aim for a dynamic compression ratio of around 8:1 compression. I know dynamic compression ratio calculation is a difficult concept to wrap your head around the first time. I just learned it last winter. But if you want to build your motor right, you have to learn the rules.

EXHAUST- stock single exhaust manifold or dutra duals. For a single exhaust, run 2 1/4 pipe all the way. For dual exhaust, run two inch pipe that y-s into a 2 1/4 inch pipe, or run dual 2 inch pipe all the way back.

INTAKE- in a truck, especially a 4x4, you won't see engine RPMs that would require much beyond a two barrel carb. I say stick with the factory "Super Six" two barrel intake.

CARB- again, your motor just won't out-breathe a two barrel. A Carter BBD flows 280 CFM and would be just fine. Or you could run a Holley 2300 that flows 350 CFM.


You can build the motor you say you want, but it takes careful planning, measuring, and a willingness to learn how everything works together. THe above is just my recommendation, take it or leave it. I strongly encourage you to not take my word for anything and to learn the ins and outs of what you are doing before you spend any money on any fancy parts.

EDIT: Doc beat me to it. I would listen to him before I ever listened to me.

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Casually looking for a Clifford hyperpak intake for cheap.

Reed gives more detail and sound advice... I gave quick list of parts and settings that will result in lots of low RPM power on pump gas.
Attention to details and matching the parts (and assembly work) to the intended use, is key.
DD

Jimmy,

Read up on my build for "Torque and mileage" in the FAQ sticky under Engine Matrix.

Doc gave you a pretty nice build!
He is the master!

Mine is one step below it using the E254 cam (.435 on both lobes) and going to 9.5 to 1 to increase the torque.
It has mega punch and lots of power.....
with 2.25" exhaust,
distributor recurve,
electric fan,
lots of porting, etc....

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

All righty then thank you dart270 dont think i want to spend 1000 on valves that are only 5 percent bigger seems like a waste on a 4WD long bed with a manual trans, AS for the doc howdy, your a hard person to talk to, i couldnt find your email anywhere till now . Can i call you mr D! hehehee thanks for your advise i live in portland ore, AND will this combonation pass DEQ? Now also i was told by a friend that if i take out the flapper in the stock exhaust manifold it would still heat the intake but would also lessen exhaust back pressure do you think this is true. I think i need to stay with the stock 2 bbl manifold and exhaust because for 4 months its in the 30 to 40 degree range do you have a opinion on that. Above all and i know everyone says this i only want to do this once, knowhatimean vern, i mean mr D. sure would like to talk on the phone sometime to make sure i fully understand what your tellin me, hit me back everyone , this could be the funnest thing ive done in a while

I would leave the heat flapper in there. Make sure it turns freely, then leave it alone.

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Casually looking for a Clifford hyperpak intake for cheap.

Portland, Oregon. Thats my part of the world. Dad was a police officer there for a looooong time.
They have given great advice here. I don't think he meant $1000 on just the valves, but on the head for a "big valve head" ( I just breezed through this thread). The Erson cam is an absolute must as well as trying to get the compression to an honest 9:1 or so. Don't have to get crazy, but it will bertanly help. I've never had luck with large overbores, minimal cubes for the investment. I've always tried to by a block with a fresh bore an pistons than worry about that.
Around this part of the world there is Richard (Fopar), CJ, DI, Josh is a little bit North of you as well. Sorry if I forgot anyone!

I forgot, are they giving your vehicle the idle test, or are you in the year range they have to run the vehicle on the "dyno"?

If it's an idle test, things should be easy to adjust to get it "lean", the run test will be a bit harder, need some tuning.

???

-D.Idiot

Hey duster Deq did not put my truck on the rollers, just tail pipe, i did have to rev to 2500 and then back to idle So with ajustments it will pass DEQ Welllll i can live with that every 2 years. Does that cam make it idle with the lope or just regular BYE for now

Runvs826 Howdy neighbor, I actually live in sherwood, 10 mile south of portland, 1000 dollar was a quote fron the local machine shop here for valves, seats, and the labor.That seemed alot. Do u think just milling the head will get me where i want to be. It will never be a race car, i know that, but it would be nice to be able to stay up with traffic on the hills, Right now if my RPM gets below 2500 on a hill i cant stand on it and it just seems to slowly lose power. My tack read 3000 at 65. If someone dont slow me down i can maintain it, But as we all know theres allways someone who passes u just to slow down in front of u, then im stuck till flat ground. Who are the dudes u told me about

Reed, So the heat riser flapper doesn't create back pressure,even in the cold weather,cool less work for me to do, What made me ask is the flow thru the stock manifold seems like it would be greater without it during the transition from cold to hot, or if its cold out would it stay partical closed and restrictive Dunno thanks for the info