360 flat tops wirh Edelbrock heads

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I kinda had the same built 360, same pistons .003 in the hole and speedmaster heads. It was in a 5,000 pound truck with a tiny little cam. ****, my cranking compression was like 230-240psi. I only have pump 91. I blew a head gasket. Had 1009’s. Something wasn’t right. LOL.
 
I entered all of the information that the OP gave for calculating his compression ratio and I got 9.87:1. The pistons are .005" down the bore add that to the headgasket thickness gives .041" quench distance, 5cc valve reliefs. Headgasket thickness is .036". Bore is 4.030" headgasket bore diameter I figured at 4.100". 63cc combustion chamber size. Stroke is 3.580".
 
I refigured it with using 0 for the valve relief and I got 10.43:1. I used the GT compression ratio calculator. I don't know if I missed anything but I tried it twice and both times I got 9.87:1 .
 
I found what I did wrong in figuring out the compression ratio, I was wrong, my bad SORRY about that it is 2am in the morning
 
rumblefish360 said:
Maybe….

Not seeing it.


I love manual transmissions. Knowing your first gear ratio is a really good thing to know. I do have one thing though, I’d like to say, the 3.55’s will limit camshaft size or you’ll be a dog out of the hole and a screaming top end that will take a long time to get to.

In the other post, you mention a cam duration of 243. IDK the overlap amount…. But a duration like that would (strictly IMO) of at least 3.91 with small tires (smaller than 27 inches) and 4.10’s as a min with a taller tire like at 28 inches.

(I’d do 4.30’s on a 28” tire.)

Oh! I know…. I know…. Been there done that still doing it!

So tell us here… what’s “Fast” for you and are you more so in the street or track?
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I can't confirm the 1st gear ratio, its a non overdrive A body 4 speed so it should be 2.66. I do have a 391 pig I can use, Im wide open on the tire size. Thats another thing on the shoppin list. I may relocate the springs inboard and do the mini tub.
Fast?? Well its a 90% street car. I dont really figure on taking it ti the track but ya never know.
 
My Edelbrock headed 340 was 11.4-1, all I ran was pump 93. The cam was 237/242° @ .050".
 
You should hit up Mderoy for his combination. He car runs really well and there’s not a ton of trick parts in it. I’ve seen him go down the track.

He does have an OD automatic and IIRC, 3.91’s out back.

I asked what your first gear ratio was because if you take the first gear ratio and multiple it by the rear end ratio, the closer you get to a 10.00 the better off you are.

If your below it, more gear, if your above it, less gear. Though the rest of the trans gears come into play as well….
 
Something close to the MP 528 would be a good start. If you use the 3.91 gears…
Bullet cam symmetrical solid lifter
camshaft ground on a 107 LSA / 104 ICL
Lobe# FC371/365
Duration @ .020 .050 .200. Lobe lift
FC271/365 271 242 159 0.3650
Lobe Lash
0.0120 X 1.5 = .018 lash .548 lift
CRA = Conventional Lobe / RPM /
Asymmetrical lobe profile
Tight lash, mechanically efficient design with fast opening and slow closing rate.
57 degrees of overlap
 
33IMP said:
I've liked the specs on just about every Voodoo I've looked at.
I hope their qc is still good, now that holley/comp cams ate them up!
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I just installed a 251/259 @ .050 Part #30300742 in a 360 I'm putting together and the degree and lobe lift were perfect.
The #30200741 I currently run in my 340 got the job done with a 8.75 4.56 gear 28 inch tire. 11.64 I've been beating on the 340 for over 10 years so the 360 is the next mule to experiment with.
I put a Dana 60 4.10 and 26 inch tire in preparation for the 360 and lost a tenth.
 
mderoy340 said:
I just installed a 251/259 @ .050 Part #30300742 in a 360 I'm putting together and the degree and lobe lift were perfect.
The #30200741 I currently run in my 340 got the job done with a 8.75 4.56 gear 28 inch tire. 11.64 I've been beating on the 340 for over 10 years so the 360 is the next mule to experiment with.
I put a Dana 60 4.10 and 26 inch tire in preparation for the 360 and lost a tenth.
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This one?

Solid Flat Tappet. Pro Street/bracket race cam with good mid range to high end torque and HP. Needs 3200 RPM stall converter, headers, 11:1+ compression, 3.90+ gearing. Rough idle.; Advertised Duration (Int/Exh): 280/288; Duration @ .050 (Int/Exh): 251/259; Gross Valve Lift (Int/Exh): .566"/.586"; LSA/ICL: 110/106; Valve Lash (Int/Exh): .016"/.016"; RPM Range: 2800-7000; Includes: Cam Only
 
Pics of the Porting in the W@ heads, They need cleaned up, The chambers look to be polished
 

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mopfried said:
Thinking of a cheap build with avaiable parts that i already have.
360LA block with H116CP speed pro .030 over pistons, .005 in the hole.
Set of Edelbrock untouced (used, not ported) RPM 63 cc heads Quench closed chamber)
.036 head gasket... comes up as 10.6 static compressio.
4 speed in a dart. \
I know i need to be careful picking camshaft, but will 10.6 be too much compression for pump gas?
Hot street motor.. headers, 355 gear ..maybe fuel injection...

I have never ran aluminum heads.....
I have some W-2 iron heads (70 cc and no quench, Open chamber, ported) and all it take to run them except pushrods.
Thanks in advance,
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TT5.9mag said:
I’d be willing to bet it didn’t have an 1800 rpm converter and 3:55 gears.
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Please show me where the OP mentioned an 1800 rpm converter in his first post. Kinda hard to have a converter with a stick, LOL.

3.55's wouldn't have been a problem with that 340, probably could've got by with a 3500 rpm converter..
 
mderoy340 said:
I just installed a 251/259 @ .050 Part #30300742 in a 360 I'm putting together and the degree and lobe lift were perfect.
The #30200741 I currently run in my 340 got the job done with a 8.75 4.56 gear 28 inch tire. 11.64 I've been beating on the 340 for over 10 years so the 360 is the next mule to experiment with.
I put a Dana 60 4.10 and 26 inch tire in preparation for the 360 and lost a tenth.
Click to expand...
That's VERY interesting. Do you think it was less gear, shorter tires, or more weight that caused you to slow down?
 
justinp61 said:
Please show me where the OP mentioned an 1800 rpm converter in his first post. Kinda hard to have a converter with a stick, LOL.

3.55's wouldn't have been a problem with that 340, probably could've got by with a 3500 rpm converter..
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Easy, It was a joke, and not pointed at you. I was more making an effort to show that the compression and fuel are only a few variables in a long list of important factors that determine if an engine will detonate.
 
rumblefish360 said:
This one?

Solid Flat Tappet. Pro Street/bracket race cam with good mid range to high end torque and HP. Needs 3200 RPM stall converter, headers, 11:1+ compression, 3.90+ gearing. Rough idle.; Advertised Duration (Int/Exh): 280/288; Duration @ .050 (Int/Exh): 251/259; Gross Valve Lift (Int/Exh): .566"/.586"; LSA/ICL: 110/106; Valve Lash (Int/Exh): .016"/.016"; RPM Range: 2800-7000; Includes: Cam Only
Click to expand...
yes
 
33IMP said:
That's VERY interesting. Do you think it was less gear, shorter tires, or more weight that caused you to slow down?
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less gear. When I ran the 4.56 gear with 28" tire I crossed the stripe at 7K rpm. Low gear set 999 got me out of the hole. Short stroke motor needs to rev. My converter flashes to 3400 and a higher stall would help with the 4.10 but that's more $$$ and I drive 50 miles to run at the track, so the converter I have is staying as is.
 
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