The felpro 1008 is 4.180". I think I'd lay it on the head and see how much I could open her up.
340 stroker 422
- Thread starter Miszny
- Start date
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Too many variables because DCR uses the intake closing event. So what influences how much air [ by weight ] is drawn into the cyl until the int valve closes:
- cam overlap [ LSA ]
- lobe lift
- how well the port flows
- the exh system
- the intake manifold flow characteristics.
All of these parameters will affect the total amount of air the cyl captures, but DCR only uses the IVC point.
The OP has 'nicely ported' RPM heads. This alone you would expect would flow better than stock heads, yet the DCR number would be the same!
- cam overlap [ LSA ]
- lobe lift
- how well the port flows
- the exh system
- the intake manifold flow characteristics.
All of these parameters will affect the total amount of air the cyl captures, but DCR only uses the IVC point.
The OP has 'nicely ported' RPM heads. This alone you would expect would flow better than stock heads, yet the DCR number would be the same!
And if you understand the whole package, it’s not a problem.
I myself don’t bother with the dynamic calculations as it’s a PIA. I understand the relationship ship of the static and the intended cam to be used & the overall interface ended purpose of the build. The whole recipe must be looked at and understood. I haven’t crossed every bridge but it’s been fun finding out when you go to far and what to do about it.
I myself don’t bother with the dynamic calculations as it’s a PIA. I understand the relationship ship of the static and the intended cam to be used & the overall interface ended purpose of the build. The whole recipe must be looked at and understood. I haven’t crossed every bridge but it’s been fun finding out when you go to far and what to do about it.
I don't think it's a real problem, just a slight problem to solve if any at all.
Where's AJ.
11.8:1 don’t you guy think aluminum heads will take that?
I’m not sure what your saying or asking but it’s an octane issue IMO, but if he’s willing to try it as is, and it works on his best pump fuel, I’ll be happy to see it work and be wrong about the whole matter.
Depends on a lot of factors. I follow a head porter on YouTube by the name of Eric Weingartner, cool guy that just talks about head porting. Mostly Chevy stuff but he talks a little bit about mopar stuff from time to time. Anyhow he has a 12.something to 1 chebby he swears has no issues with pump swill. His truck is a pretty light S-10, big cam, plenty of converter and gears as well.
Plenty of factory cars these days with higher compression ratios. These are very finely tuned of course. Having full control of fuel and timing helps a lot.
My stroker will be about 12:1 if I stick with my current heads. It will have good quench, big cam and converter etc. But I just want a race car to drive to the coffee shop etc. If I have to run it on e85 I'll do so.
Plenty of factory cars these days with higher compression ratios. These are very finely tuned of course. Having full control of fuel and timing helps a lot.
My stroker will be about 12:1 if I stick with my current heads. It will have good quench, big cam and converter etc. But I just want a race car to drive to the coffee shop etc. If I have to run it on e85 I'll do so.
Demonic
Well-Known Member
I've been wanting to start a thread on this particular fuel additive, but I'll just leave this here. A friend with a blown 392 runs it in his '30 Ford hot rod, well over 12 pis boost:
bndautomotive.com
ACES IV Gasoline Formula « BND Automotive
bndautomotive.com
Wow so many responds!
Heads are Edelbrock rpm, photos attached. They were bought bare and fully done with good parts.
I didn’t cc them, nor the pistons.
Heads should have 63cc chambers and pistons have 6cc valve reliefs.
Heads are Edelbrock rpm, photos attached. They were bought bare and fully done with good parts.
I didn’t cc them, nor the pistons.
Heads should have 63cc chambers and pistons have 6cc valve reliefs.
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Camshaft is small because it’s all going into a hot street car with gear vendors overdrive. I was shooting for a lot of torque but I overstepped a bit.
I hate dished pistons in big blocks because they always limit engine evolution, so lack of small blocks experience made me get these.
I was hoping quench would save my ***, or perhaps 93 (European 98) with octane booster?
I hate dished pistons in big blocks because they always limit engine evolution, so lack of small blocks experience made me get these.
I was hoping quench would save my ***, or perhaps 93 (European 98) with octane booster?
The chamber could use a little work, I'm surprised they didn't touch it during porting.
That’s probably going to be some way out. I can work on the chambers but it’s not going to make that much of a difference.
Purpose of this is to make good power and torque on the street.
Also engine needs to make good vacuum for power brakes.
Unfortunately no e85 here at all, but these is 100 octane pump at shell gas stations.
Rat Bastid
Dunamis Metron
You *should* be able to run that on pump gas IF you do everything you can to help it.
Do NOT put the cam in at 104. I’ll run the numbers a bit later but I’d put it in at 107 or 108. There is zero sense shutting the intake valve 3-4 degrees early and shifting the overlap triangle.
Make sure the distributor has a curve in it. And not an “all in” by 2500 RPM. You need an actual curve.
Spark plug heat range is HUGE. You can’t just pick up a plug catalog or search the web and pick a plug. Most likely you will NOT be able to use an extended reach plug. Whatever you do, heat range is critical.
Get your coolant temp under control. That means no hotter than 160 degrees. Ever. You need as much coolant flow as you can get. You can’t get the radiator big enough.
Make sure you understand how to drive correctly. The number one issue with higher than orthodox pump gas compression ratios is loading the engine into detonation.
Any idiot can lug an engine in to detonation. That means if you are using an automatic you need to reach over and downshift if the programming isn’t perfect. And it’s usually not.
Same thing if it’s a stick. Lugging the engine below peak torque is an engine killer.
If you are going to use an OD, make sure you don’t cripple it with too high an axle ratio (numerically lower). Pay attention to your cruise RPM. Again, lugging the engine will force you into detonation.
You can make this work. You just have to think it through.
33IMP
Well-Known Member
Okay, here "pump gas" premium varies depending on location from 91 to 93. 100, unleaded or leaded, is considered race gas, and is at least twice the price of pump gas.
Is your 100, just top end pump gas, compared to your 98(?) premium, or really more like race gas?
My guess is that you will need the very best pump gas, plus some kind of octane booster.
Is your 100, just top end pump gas, compared to your 98(?) premium, or really more like race gas?
My guess is that you will need the very best pump gas, plus some kind of octane booster.
Axle ratio is 3.91
Cam after retarding 2 degrees came out at 104.5 icl
I was thinking to install it at 106+
Rat Bastid
Dunamis Metron
At 108 your overlap triangle is centered (where it should be) and you are closing the intake valve 4 degrees later (@ .050) and that’s two big things.
I also question your gear selection. Unless you have a very short tire you will constantly be lugging the engine, or at least be far enough below peak torque that you are on the edge of detonation.
I was thinking about doing something like this also, but was not sure if I should do 4.180 with 4.100 bore…
I will cc the heads. Valves are not from Edelbrock.
It will make more of of difference than you think, if done right. The chamber has a lot to do with detonation.
Did use use the 0.039 x 4.180" head gasket in your calculation or the 0.039 x 4.04".
Rat Bastid
Dunamis Metron
You have to be careful opening the chamber up bigger than the bore.
You can create more issues doing that.
Tire will be 27 or 28” tall, copper cobra 275 or 295.
I was planning to use mild timing curve in msd distributor, also limit max timing and use cold plugs.
4.180 gasket, bore is 4.100…
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