X block sonic test

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12swinger

12swinger

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I have my block back from the machine shop.
Sat over at his shop awhile, as his sonic tester didn’t come back after loaning it out. he purchased a new one, and said it’s pretty safe to bore to at least 4.100 with a little block fill maybe more.
currently it’s a fresh 4.04 as the block was ran as a .030 over 318 bore.
Thoughts on potential bore size?
Is decking some a good idea?

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Not sure what you mean by a '30 over 318' and '4.04' as those are not the same thing. As for bore, there is no way I'd go to 4.10 if it required any block fill. Leave it smaller and you'll never know the difference.
 
I’m not a fan of taking a block to max bore size just because it will take it. I’d rather use a bit less bore and leave some room to go to the next oversize.

You can get pistons and rings in virtually any bore size. So maxing out bore size isn’t my thing.

If I was going to do anything with your block, and I wanted more bore, I’d probably go to a 4.080 bore and then you can go up in .005 increments from there if you need to go bigger from there.
 
gregcon said:
Not sure what you mean by a '30 over 318' and '4.04' as those are not the same thing. As for bore, there is no way I'd go to 4.10 if it required any block fill. Leave it smaller and you'll never know the difference.
Click to expand...
The block was previously ran as .030 318
I bought it with a fresh 4.04 bore.
 
I have run partial fill in a street engine with no problems. Full fill is for race applications only in my opinion, never tried it on a street engine. The fill just seems to tighten up the bottom end of the 2 bolt main small block for less twist of the caps. As far a the 4.100 bore, that might be iffy for the street.
 
I'm with the majority. Keep it a conservative bore size and save it for future freshening. Extra thick walls will keep the bores more stable & round. 4.04" is a good start if it gives the pistons proper clearance. They may not be as expensive as a bigger, less common bore. Deck should always be checked as part of the "blueprint" process to make sure everything is flat, equal, square, etc. with consideration to tweaking compression.
 
I was thinking another .060 would bring the bore to 4.100
And a 4” or 4.100 stroke
The cylinders would still be around .250 versus .300 thick.
I guess I get the mindset of less is better.
I am struggling with my wife having the bigger engine. Lol I guess it’s meant to be.
 
12swinger said:
I was thinking another .060 would bring the bore to 4.100
And a 4” or 4.100 stroke
The cylinders would still be around .250 versus .300 thick.
I guess I get the mindset of less is better.
I am struggling with my wife having the bigger engine. Lol I guess it’s meant to be.
Click to expand...

It doesn't have to be bigger in order to be faster!
 
gregcon said:
Not sure what you mean by a '30 over 318' and '4.04' as those are not the same thing. As for bore, there is no way I'd go to 4.10 if it required any block fill. Leave it smaller and you'll never know the difference.
Click to expand...

yep. X block comes 3.91 ish bore. So 30 over would be 3.94
They usually will go 4.070 with no issues. I had one i ran at 4.100 and had enough at that bore for a freshen with a custom piston( would try to avoid going all the way out to 4.125)
I am not a concrete in the block guy, so I prefer Lots of meat and not a questionable bandaid
 
25 years ago, I had an a-hole (Bill Richardson at RAM) talk me into partially filling a mint 1966 Street Hemi block with hard-block. It was an important part of his machining package. Got the engine back, and within a few weeks it developed a horizontal crack about 6" long in the block, following right along the top edge of the hard-block. Since then, I've been a non-hard-block guy. As for the Hemi, at almost the same time, it has the #1/2 rod journal swallow a glob of orange silicone that a-hole had let float loose, so the custom $2500 Crower lightweight crank and two of the custom 7.400" Crower lightweight rods were scalded along with the block.
 
Just washed the Challenger as I’ve been driving it the last 3 days straight. Pretty cheap to drive with gas prices so low.
This car turned out so pretty,
Got the headliner in, and half the carpet.
Pulled the wheels and put the correct centers on.

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A lot of power is made in the heads and cam. I built a 318, .030 over with ported x heads and a nice cam. 4 speed car. 73 cuda and I smoked my buddies 70 camaro with a built 350 and 4 speed. 4.040 is stock 340 bore if thats what you measured it at. I loved being able to say, yea its just a 318 in there. Lol.
 
B3422w5 said:
yep. X block comes 3.91 ish bore. So 30 over would be 3.94
They usually will go 4.070 with no issues. I had one i ran at 4.100 and had enough at that bore for a freshen with a custom piston( would try to avoid going all the way out to 4.125)
I am not a concrete in the block guy, so I prefer Lots of meat and not a questionable bandaid
Click to expand...
I almost bought one that was 4.165
They claimed it’d go 4.180
I couldn’t pull the trigger, as it seemed a one shot build.
 
Last edited:
MerlinsMopar said:
A lot of power is made in the heads and cam. I built a 318, .030 over with ported x heads and a nice cam. 4 speed car. 73 cuda and I smoked my buddies 70 camaro with a built 350 and 4 speed. 4.040 is stock 340 bore if thats what you measured it at. I loved being able to say, yea its just a 318 in there. Lol.
Click to expand...
I have some w5 heads I’ve got as far as I’m comfortable going on the port work, and no holes yet. My machinist said let’s sonic test them.
I have some w2 heads that are done on another engine, I’ve not flow tested but are pretty maxed under the valve, with 2.08 intakes. Paccalloy springs, ti retainers, Strip dominator intake, and a M1 for the w5 heads.
 
12swinger said:
I have some w5 heads I’ve got as far as I’m comfortable going on the port work, and no holes yet. My machinist said let’s sonic test them.
I have some w2 heads that are done on another engine, I’ve not flow tested but are pretty maxed under the valve, with 2.08 intakes. Paccalloy springs, ti retainers, Strip dominator intake, and a M1 for the w5 heads.
Click to expand...
Oh splat! I'm stuck with j and x heads and never got to try any of the w2 w5 stuff but i did jam a 2.08 in a set of x heads. Haven't got to fire that 1 up yet tho.
 
MerlinsMopar said:
Oh splat! I'm stuck with j and x heads and never got to try any of the w2 w5 stuff but i did jam a 2.08 in a set of x heads. Haven't got to fire that 1 up yet tho.
Click to expand...
I’ve had a lot of fun with some J heads, albeit they were water sprinklers.
 
gregcon said:
25 years ago, I had an a-hole (Bill Richardson at RAM) talk me into partially filling a mint 1966 Street Hemi block with hard-block. It was an important part of his machining package. Got the engine back, and within a few weeks it developed a horizontal crack about 6" long in the block, following right along the top edge of the hard-block. Since then, I've been a non-hard-block guy. As for the Hemi, at almost the same time, it has the #1/2 rod journal swallow a glob of orange silicone that a-hole had let float loose, so the custom $2500 Crower lightweight crank and two of the custom 7.400" Crower lightweight rods were scalded along with the block.
Click to expand...
Man that really sucks!
 
Kinda one of the reasons I flow my heads on an adaptor that measures 4.010. That way I see how they react with the valves I’m running. In the back of my head I know if anything it will
Flow better on my 4.030 stock block and 4.100 R3 block.
 
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