camarokev400

Well time has come to tear into the motor again:
Here is the situation:
406
dart iron eagle 200cc runner 64cc chamber 2.05/1.60 valves
keith black 30cc dish pistons
performer eps intake
demon 650 mech sec
eagle rods and crank
xe274 cam 487/490 lift 230/236 duration at .50
Comp roller tip rockers 1.52 ratio

What can i do to get more power, I have already bought a rpm air gap intake. I know i need different pistons to get more compression but what should i get. Also thinking about a retrofit roller cam (needs to be small base circle) maybe xr288? Last year with this setup, it dyno'd 290 rear wheel hp on a mustang dyno and then the rearend broke. Also want a 6000rpm max, and the car is only driven on weekends and racetrack sometimes.

other car specs:
3.73 gears
th350 trans
holeshot converter 2500-2800 stall
hedman long tube headers
2 1/2 inch true dual exhaust with h pipe- dumps in front of rear end

miami79

bigger cam would help, the carb looks small, think a 750 mech would do you well with the bigger cam. is that the old ie heads? if so you could always look in to a new pair if your willing to pay that kind of money. Good luck.

camarokev400

yeah they are not the new iron eagle platniums. When i called demon they told me to get that 650 and i knew i shouldnt have but i listened, now everyone tells me to get a bigger carb....

F-BIRD'88

do you want a "Pump gas" motor or is race gas in the plans?

Confuzed1

iTrader: (4)

Oh man! That's exactly what happened to me! I even questioned them, saying that a 750 would be in order...

We seem to have simular setups...I really have no power probs, Always looking for more... -But I've never had it on a chassis dyno either.

Just so happens I've just gotten together all the parts I'll need to go retro roller. I should have it all in and running soon.

sofakingdom

iTrader: (1)

Unfortunately, it looks to me like the pooch may already be porked; as of the time the short block was built.

64cc heads, 30cc pistons, .025 (stock) deck clearance, .039" (1014) head gasket: gives 8.7:1 compression. If the deck clearance is more like what I'd expect in a rebuilt motor, since most aftermarket pistons that aren't custom racing sort of ones have a deck height .020" lower than stock, then your CR is an amazing 8.4:1.

You already have too much cam for that little CR. You might want to try going the other way with that; a smaller cam. The cam you have should be OK though, I don't think there's much to be gained either way, with such low compression.

Your intake is too small for that many inches. A Performer RPM would make an amazing difference.

I don't really think the carb is the "problem", although if the motor could breathe better (intake manifold), that might be a different story.

If pistons and short block work are an option for you, I'd suggest getting some pistons with a 1.56" compression height if those aren't (likely not....get something in there that is) and a dish of around 22cc. Zero-deck the block to them.... VERY important. That combo will give you about 9.8:1; which is about right for that cam, and will allow you to take advantage of the heads' flow.

Or maybe, try a blower.

MaxxMitchell

iTrader: (4)

The compression change will make a pretty big difference, and will bring your combo all togeather. Get a Performer RPM, or the RPM AIR gap, and possibly a larger carb. What headers are you using? Maybe give the heads a once over with a die grinder?

Is the crank a forged piece? What rods are they, the I beams or H? If your running the forged crank, and H beams, a blower would be a fun choice and you wouldnt have to tear into her again.

camarokev400

the crank is a eagle non forged, and the rods are eagle sir 5.7's. How about a 10.5 compression... would that be pump gas friendly? Was looking at flat tops with 4 valve releifs said like -12.5ccs?

Confuzed1

iTrader: (4)

Me personally, I think 10.5:1 on iron heads is pushing it. The big question is, what is your compression ratio? 8.4:1 IS too low. -but not bad for a blower..

I run the 70cc (72cc shaved) iron eagles with KB-147 (-18cc dish) pistons and ended up at around 9.5:1. Maybe that's the difference, but I'm no expert.

miami79

missed the cr before, the motor sure need some more cr to run good and as sofakingdom said zero deck it for some quench, and then go with bigger cam and carb (you allready have the rpm intake right?) i would probebly stay below 10 for cr if your not going with race fuel.

camarokev400

allright so if stay 10 or 9.8 i would be good? How much gain could be expected from just pistons alone? and yes i already have the rpm air gap intake. how about these pistons?
http://cgi.ebay.com/ebaymotors/Speed...QQcmdZViewItem



and here is a link to the dyno sheet
https://www.thirdgen.org/forums/atta...9&d=1119143380

1bdbrd

iTrader: (1)

i would suggest like others have said to bump the compression somehow. im also a fan of aluminum heads and if thats within your budget i would suggest those as well. maybe a bump to hooker long tubes with the 1 3/4" primaries, and also switch to an x pipe over an h pipe. those mods alone (with the same cam) will yield great results.

ME Leigh

Supercharger or turbo time!

ME Leigh

Supercharger or turbo time!

camarokev400

no... that would require all new parts also.. forged everything and get rid of the keith black pistons... want to stay NA no power adder

F-BIRD'88

Have you track tested this combo, as is? Et... MPH... 60ft...

To cure your compression problem you have a few ways your can go.
replace parts ( pistons) or machine deck clearance and head volume to get it up to where it should be. Don;t assume your heads are actually 64cc. probabily larger (67-68cc) only way to tell is to measure them.

By the time your done you'll be an expert on "Blueprinting" a motor.

MaxxMitchell

iTrader: (4)

What head gasket are you running? You could always switch to the MLS Felpro thats .015" thick.

Also with the heads off you could do a little porting as well. Port match the intake/headers to the heads. If you can find a set of Hooker 2210 long tubes.

camarokev400

Head gaskets, im not real sure what is on there but i know they arent specially thin ones..... they are just fel pros with steam holes.

As far as track testing no not really

My old setup same bottom end, only difference was stock 350 heads 64cc 1.94 1.50 valves, xe 268, performer rpm, stamped non roller rocker arms, performer 750 carb. I ran 13.5 with 1.8 60 foot times.

with all i added i figured i would feel alot more power. with more cam, better heads, better carb, roller tip rockers, only thing i know killed me was the performer eps intake but i dont see the intake holding it back that much.... you guys think just putting the rpm air gap on would give me anything more... i already have it so what the hell

camarokev400

i got it down to 12.7 last night, swapped out the intake to a rpm air gap, 1 inch carb spacer, and 3.73 gears on an open diff cant find a 3 series posi for sale anywhere that isnt a gov loc. Car weighed in at 3280 with me in it (170-180). I think if i could get a better 60 foot and could launch it at a higher rpm i could get a 12.5 maybe.https://www.thirdgen.org/forums/atta...ht-12.7-et.jpg

F-BIRD'88

The thinest 400SBC head gasket I could find is this copper one summit# FOG-900134175 $98.95
It's .031" compressed.
If you were to flat mill your 64cc heads to the max to intake valve seat, you should get 52cc+/-
Assuming your piston deck clearance is .025" your cr would be 9.8:1

You'll have to mill the intake face of your heads too. A machinist can help with that spec. i think its 123% of head surface cut. You'll be cutting the heads .060" to .070"
Stop at the intake valve seat edge.
Push rods will be effectively longer. Valve to piston clearance will be reduced but should not be an issue.
If you don;t want to max mill your heads you could replace them with Dart 49cc chambered heads (Dart 215) and sell you heads
Summit # DRT-10511122F $510.95
Much better than 8.4:1

mw66nova

iTrader: (13)

would that be more cost effective than getting new slugs though?

F-BIRD'88

1. Ya don't have to pull the motor.
2. Once you've sold off your old 64cc heads, yes.
They should be worth $400-800.
Don't have to rebalance the motor. rehone the block or replace bearings rings and gaskets in the bottom end.

mw66nova

iTrader: (13)

good points...