dennisbernal91z

iTrader: (2)

OK well I have made a thread like this before, but I am kinda serious about spending some money where it needs to be spent now. I finally got my new main body put on the car and dyno tunned. The car made 344 RWHP and 340 ft.-Lbs. Good thing is that I am already at 300 TQ by 3 grand. So that combined with the 4.11s makes the car get up and go right away, with enough RPM. Now, I guess just for that last little umph, I want to make the car go a little faster. I feel like I am still leaving power on the table due to my HP numbers. I see other guys with what seems to be less motor and making more power. \

WHAT AM I DOING WRONG?

The motor is a 1974 solid lifter truck block.
- 4340 Eagle crank
- Forged H beam rods
- Forged pistons
-Total seal nitrous rings
- Oh its stroked and bored (386)
- 23* trickflow heads. Nothing special, with CNC machined ports. These are teh Kenny Dewinter heads. Nothing special, might be my biggest problem.
- Hooly 750 DP with new chokeless main body and adj. air bleeds.
- Edel. Vic. Jr. intake.
- MSD pro billet dizzy.
- MSD digital 6 Plus box
- MSD blaster HVC coil
- Big 8 - AN feed lines and running 93 ALL the time.
Cam specs:



The static comp ratio is around 10.4 and the dynamic is around 9.5. Nothing crazy.

Would my best bet at making more power, and really livening this thing up be upping my comp ratio with dome pistons and a set of AFR's matched with an appropriate cam?



Also let pretend that was what was needed. Do you think that this would make me loose MPG or gain? Only reason I am staying away from forced induction is gas millage. If supercharging didn't make it get worse I would just go that route.

As of now I am just relying on N20 to go faster.

Also what are the benefits of a direct port N20 system? Any benefits if I am just want no more than a 250 shot? Can you make more power with less N20? please fill me in with any info you guys have. thanks

-Dennis

Orr89RocZ

iTrader: (20)

what was peak power at?

couple of things to look at. those cam numbers look pretty good. should easily make 400whp in the right head/intake combo.

Make sure your not hitting any kind of valve float that is keeping the motor from pulling up top as again, you should have more power than that.
Make sure the ignition and timing are tuned right.

With that cam, i'd like to see more like 11 to 1 compression and a trickflow 215 head. or AFR 210's. 195's should work but will need ported out alot. you need more flow to get the true benefits of that cam.

dennisbernal91z

iTrader: (2)

yeah, thats what i thought.

Need more flow. My intake should be just fine, and maybe a little more carb, but probably not, if tunned right.

I think my ignition is tunned OK, the dyno guys had it for 4 hours on the dyno trying to get it all perfect.

I will look into pricing for the heads. Maybe it won't be too bad, if I just do heads.

I guess i would need to do pistons too, to get the comp ratio up

jtrescot

I would expect those heads to flow enough to support more power than you are seeing. Are you sure that it's not an overtaxed valve spring problem? Those heads are offered assembled with a variety of springs - which ones do you have? I think something else is holding it back.

dennisbernal91z

iTrader: (2)

These are the ones that I have.

http://store.summitracing.com/partde...0&autoview=sku


What is the easiest way to make sure these are the parts that are on my car? I would assume there must be a casting #. I will look for it and see what I can find. Also maybe I screwed my self on break in. Maybe I need a leak down test and all that stuff.... Any insight on that?

I did have a really hard time getting this thing to run right. This is the car I learned everything on... So it has gone though a lot of "learning" with me.

I hope I didn't mess anything up. I guess if I did, sux for me, but I would just use the oportunity to up the comp. ration.

Any idea what is going on.!!!!??

Orr89RocZ

iTrader: (20)

best way to check is to take a spring off the cylinder head and measure its specs with a spring pressure gauge. Measure spring diameter, and check for single or dual springs etc. that should give you an idea of what trickflow has given you. Measure the installed height and pressures at that installed height. From that you should beable to tell what springs you have

i also agree that those heads should support more than 344 whp. was this on a mustang dyno? those i have heard read less than dyno jets

SpitotRs305

your dynamic compression is in the pooper... no where near 9.4 try like low 6s that is a pretty mean cam to only run 10.4 CR... you need more compression

327???

That seems kind low, what does it run? According to my weight and MPH I put down ~330 to the wheels with 30 less ci, a WAY smaller cam(215/215), and the same compression.

That dyno may have been off, corrected MPH at the track is more accurate.

SpitotRs305

or my favorite one... have you made sure your throttles are opening completely? not just can you open them by hand but can you push the pedal to the floor and completely open the throttles... i have seen that a couple of times where you can fully open the throttles from the carb with the throttle cable hooked up so it was assumed that they were fully opening.. not until it was actually tested did i start banging my head

jtrescot

This kit:

http://store.summitracing.com/partde...0&autoview=sku

claims to make 500hp with what looks to be almost an identical cam and your heads. Something isn't adding up.

dennisbernal91z

iTrader: (2)

Right. I know that 500 is based on fly HP and not RWHP. but still, it should be near 430 I would think. Since
500= perfect everything on an engine stand.
480 (about)= real world engine stand
400-420=real world rear wheels.

As for the throttle opening all the way. I honestly have no idea. I will check this afternoon.

And yeah, i guess the comp. ratio is low. Kinda a lot of work to change that though as I would need to open up the motor and so on. If it is really is that low, I think I would toss a precharger on there first. haha. Don't wanna open up this motor with only 3000 miles on it.

I drove well over 100 MPH on the freeway getting to a car show this weekend for over an hour and mechanically the car ran perfect. So I am inmpressed with how she is running now. Not a drop of coolant, oil, anything. Just pulled hard and get this... at 110 MPH, RPM in 6th gear ---> 2500 haha. This things top speed must be pretty high with a red line of 6700.

Anyways, I guess my weakest link is my compression. I will check out my throttle opening.

Orr89RocZ

iTrader: (20)

just get the heads milled and check for piston/valve clearance afterwards. few cc's will bump that compression up

dennisbernal91z

iTrader: (2)

Like how much? I know you can mill the heads, that would be something that I wouldn't mind considering. I know the final #s will be done my a machine shop and so on. But can someone give me a ballpark estimate about what i could get that 9.4 up to? We taking a few hundredths, like 9.8 or can this milling bring me up to 10.5? (safely of course)

i just have no idea. Thanks for the insight. I will start doing the initial research to learn about the process and all that. Thx.

SpitotRs305

milling just a few thousands off i mean like .002 might drop about 2-3cc's depending on the head... however rolling them might be a option also

dennisbernal91z

iTrader: (2)

Sorry for being a newbie, but whats rolling?

All the research I have done in the past about heads always involved just buying the right head and bolting it on. Please fill me in.

I know there are a lot of things that can get done to heads and that there is a lot of power to be made with a nice set.

My bottom end is pretty bullet proof being all forged and with only 3000 miles.

Kinda with I had spent more $ on heads, but the forged parts were just so damn much. Playing with N20 is fun though. haha.

sofakingdom

iTrader: (1)

Rule of thumb on SBC heads is, 1cc for every .006" of milling. Not precise but at least puts you in a ballpark.

"Rolling" is what some people cal angle-milling, because it kind of "rolls" the heads outward toward the exhaust. Since the chamber is over on that side, you can get a bigger change with less milling, than milling them flat. Problem is, the head bolt holes also "lean" over, so if you use much of an angle at all, you have to re-drill them; and of course, the intake face of them has to be adjusted, too. I'd avoid that.

Are you ABSOLUTELY POSITIVE about your compression now? Specifically, what is the EXACT deck clearance measurement you got BEFORE you put the heads on? If you don't know, you need to, BEFORE making a decision about what to do next. Ideally, you want .000" (pistons exactly level with the top of the block).

By my calculations, with the bore & stroke you have, 72cc heads, a .039" head gasket, pistons with the typical 6cc valve reliefs, and a .039" head gasket, your CR would be about 10.1 - 10.2:1, with a zero deck. It drops to about 9.6 with the stock .025" and all else the same, and 9.2 with a typical .045" such as one would have with "rebuilder" pistons such as TRW/SpeedPro.

In other words, AT BEST right now, your CR is already on the ragged edge of being too low for that cam. But, if they're more than .010" or so "down in the hole" at TDC (stock is .025"), then the pooch is REALLY already porked, and you need to either tear it down now and get the machine work done; or, figure out what you can do to get more power that doesn't involve using more cam. That's a pretty big cam, for a street motor. Putting a bigger one in than what you already have is a GUARANTEED RECIPE for slowing yourself down (making less power) than how it is now.

Kevin Vandevenne

iTrader: (3)

If the motor was not zero decked, what would be the better method to increase the compression, milling the heads or having the block decked? Obviously the amount of work to get the block machined is quite a bit more then pulling the heads, but lets say someone had the time/resources to do either.

dennisbernal91z

iTrader: (2)

I am fully aware I DO NOT NEED A BIGGER CAM, haha. It feels big as it is.

I am not sure about the decking and all those measurements. I do have all the note sheets that the builder had when he made the motor. So i will look them up and see what I can find.

Really feels like the comp ratio is too low. I really don't want to spend much $ on this motor anymore. I kinda think I will just play with it how it is and spray it when i wanna go faster.

I am not gonna go through the trouble to machine the block and probably not do the heads either. In the end this is a street car that gets driven A LOT.

Sounds crazy, but it is my DD car. so 344 N/A and 540 on the spray aint too shabby I guess.

When i am out of school I am just gonna toss in an LS2 and a blower and be done with it.

But till then, I guess i will play with the spacers and thats about it.

I will still look up the specs on the block and so on. Maybe I can gain more power from a simple cam swap, that I would consider since my motor is a hyd. roller.

86LG4Bird

iTrader: (1)

Sorry to have to tell you this, but you've already given up more gas mileage with that monster of a cam than you would have with a mild cam and a blower making more power.

Maybe I missed it, but where were your torque and power peaks?

dennisbernal91z

iTrader: (2)

Max TQ is around 4 grand and HP is around 6 grand.

Well if that is the case. Then do you think a cam and a blower would fix my "problem"?

Since I know that I have a solid bottom end, good fule suply and all the rest that is needed, do you think that adding a small 142 roots and an appropriate cam maybe, would work?

There is one for sale on here for just over $1200...

Cuz diving into the motor is outta the question this year.

antman89iroc

I learned this one the hard way. Thought I had 0.025 "stock" deck height but when I checked it measured 0.045 with flat top pistons. Kinda stupid too. I went from a dished piston with (probably) 0.025 to a flat top at 0.045. Didn't gain much (if any) compression and my quench went in the toilet. Point is that I've learned not to rely on what I think I have but to check. Little (BIG) things like knowing what my real compression is matters A LOT!

dennisbernal91z

iTrader: (2)

Yeah, if my documentation is not 100%, I will call the engine builder. Was a great guy and did great work. Bought my motor for the price of components and was given the block free. Also shipped free.

I will make sure to check. If I do decide to go ahead with the blower and smaller cam, I will do so over the winter and not till I am 100% sure what I have.

Believe me I am not one to rush into anything. I check double check then sleep on it, then check again, before I do anything to this car.

RebornFromAshes

For tuning type things I would certainly check to see that you are getting full throttle. I would also double check those valve springs. The seat pressure listed on your cam card sounds a bit low.

Still, I think your combination isn't quite working right. I don't think you have quite enough cylinder head to work with your intake, cam, and carb. Bumping the static compression ratio would help, but I doubt you will see the full potential of the engine without going to a larger set of cylinder heads.

If this is a car that you plan to drive on the street often I would opt to go back to a dual plane manifold and drop the cam size a little. You will probably pick up some HP, and you will certainly pick up some lower RPM power that will make the car faster yet. Being fast isn't all about peak numbers.

heavyduty

Very simple.. N.O.S.

RebornFromAshes

To add to what I was saying, the XR-288 from Comp Cams is a similarly sized hydraulic roller. Their recommended spring sits 132lbs on the seat. Some people still end up going up a notch because of valve float issues.

When looking at the TF web site I realized that the cam you bought is one speced by TF. Still, they have a 215cc head that was probably what they had in mind for that cam. Personally, I think the next notch smaller cam would have been the best cam giving strong peak numbers and a wide power band.

I think it would be a great idea to call up Trick Flow and talk to them. There has to be someone there that has experience with the cam and heads you are using. They could probably point out any mismatches, or at least give you information on a combo based on those heads.


If you are set on having around 550HP at the crank, or about 1.4hp/ci, and driving it on the street then you really should look at using more NOS or forced induction. That much power out of a smaller engine is going to kill efficiency at the RPM where you spend most of your time.

SpitotRs305

the mismatch is pretty obvious... getting a smaller cam will help but will still not get him to his goals... however keeping the cam he has now and raising his compression would be the best plan of action

dennisbernal91z

iTrader: (2)

I will call trickflow over the winter when I plan on organising my next steps of action.

I am pretty happy with how fast the car is now, so its not bad or anything. I am going to be tunning for a 200 shot this week, so we will see how that goes.

I will see what a spray to get me up to 544 RWHP feels like.

And I agree, getting that kinda power with no power adder is just not going to happen efficiently.

I will play with N20 this year and maybe next swap heads, cam, intake.

Hopefully I can do just intake and cam, just cuz heads are so much more $.

Thanks for all the help, in the emidiate future I will be making sure the throttle opens all the way, and playing with carb spacers on a dyno.