Mild 400 build on a budget

[Garys1969RR]

You may want to ask him what pistons he has in there, and have him measure the deck clearance. I'm sure he will relay that Info to you.

 

[400Magnum]

You may want to ask him what pistons he has in there, and have him measure the deck clearance. I'm sure he will relay that Info to you.

Yes, I asked for deck clearance specifically, along with any other information he can provide about the short block. He told another person what the part number of the pistons were, but I can’t find any specs on them. But if he’s had the block milled then knowing the piston specs won’t tell me what I really want to know anyway, so that’s why I asked for deck clearance.

 

[wyrmrider]

guys what's the name of that low cost shipping outfit, been in a couple of different threads

 

[Moparallen]

guys what's the name of that low cost shipping outfit, been in a couple of different threads

Fastenal ships on a pallet. Might try them?
Allen

 

[wyrmrider]

so what was the piston number?

 

[400Magnum]

so what was the piston number?

I don’t know, he never replied to me, and I’ve had to focus on other things and never bothered trying to contact him again. I’m just going to work on the 400 that I have, do a little here and there when money and time allows.
I got a fair deal on an engine hoist, so I can pull the engine someday and do a better job rebuilding it than trying to do it in the car. I’ve looked and the only decent piston option for me is the kb240, so I guess that’s what I’ll get at some point.

 

[wyrmrider]

240 flat tops
what heads again?
good luck with the build

 

[400Magnum]

240 flat tops
what heads again?
good luck with the build

I bought a set of the Edelbrock 75cc E-Street heads when they were $50 off. By the time I had a set of iron heads checked and fitted with new seats and guides, it was only a few hundred more to get the aluminum heads.
I went through the numbers and with a 0.027” head gasket I end up with a static compression ratio of 9.0 and an effective compression ratio of 7.7, which sure beats the factory setup of 7.3 and 6.3 respectively. For all I’m intending to do with the car, this should work out pretty well.

 

[wyrmrider]

yep
In a perfect world I'd like some quench- take time to get your advance curve right

 

[400Magnum]

yep
In a perfect world I'd like some quench- take time to get your advance curve right

Thanks, I will do that, but it’s going to be a while before I get to that point though.
Yeah, I realize the quench isn’t ideal, but its about as good as I’m going to get. If I deck the block to get decent quench, then my static compression goes too high for my cam, so I’m not sure what other ways there are to do this.

 

[mgoblue9798]

I bought a set of the Edelbrock 75cc E-Street heads when they were $50 off. By the time I had a set of iron heads checked and fitted with new seats and guides, it was only a few hundred more to get the aluminum heads.
I went through the numbers and with a 0.027” head gasket I end up with a static compression ratio of 9.0 and an effective compression ratio of 7.7, which sure beats the factory setup of 7.3 and 6.3 respectively. For all I’m intending to do with the car, this should work out pretty well.

Quench is good, but this combo as is will make a night and day difference v/s what you had.
I don't know what cam you have, but it would not surprise me a bit if the increased compression/ better heads/ better cam combo doubled the hp output of the smogger. It may even get better gas mileage- provided you can keep your foot out of it.

 

[wyrmrider]

He already has a Crane HR with short seat duration (260/270 @.004)[email protected] and 115/127 @.200 deep breather should fill those 50 cubic inch cylinders
I don't recommend milling the block enough to get quench with those pistons- you would end up with no deck
a 260 crane @.004 is like a mid 250's comp or other at .006 the .050 duration is same as the old obsolete edelbrock performer but he has a lot more area under the curve
the crane is not radical and should work good on the street with correct springs
I talked about inverse radius in another thread and here is a good example of where you have to use more duration in a roller than in a flat tappet unless you go inverse on the profile
[email protected] [email protected] 122 @200 .458 lift
[email protected] [email protected] 126 @.200 .475 lift
but then you have to consider FT break in and I'd spring for EDM lifters with these

 

[400Magnum]

Quench is good, but this combo as is will make a night and day difference v/s what you had.
I don't know what cam you have, but it would not surprise me a bit if the increased compression/ better heads/ better cam combo doubled the hp output of the smogger. It may even get better gas mileage- provided you can keep your foot out of it.

Right, I’m sure it will be a huge difference from what I had before, especially since it wasn’t in the best of shape to start with. That was my main reason for selecting this cam, was for better fuel efficiency while making the engine more responsive. It’s got 3.23 gears in it, and she’s a tad heavy, so it’d be nice to have a little more zip when I need it. Out on the highway it was pretty decent, but around town it always seemed kind of lackluster.

I don't recommend milling the block enough to get quench with those pistons- you would end up with no deck

Right, I wasn’t intending to do anything else to the engine other than check the bores and get the rotating assembly balanced with the new pistons. What I was meaning was there were only a few ways to do this as far as I know, and I was choosing to do it with the new pistons and just be happy with what I had, even though it wasn’t perfect, instead of decking. It just didn’t really come out right because I was in a hurry. Going back and re-reading it makes me wonder what I really was trying to say at the moment.

 

[wyrmrider]

I think you are spot on
vac sec carb- TQ would work
keep us posted
do you have to balance or just swap pins?
buying pistons
wish you were closer I'd give you a 440 crank and rods

 

[400Magnum]

I have a used Street Demon 625 carb that I was planning on using on an Edelbrock Performer intake. It’s got the phenolic body like the T-quad, but it’s primaries are smaller so it should be more responsive around town and still be suitable out on the highway.

The kb240 pistons and pins are about 115 grams lighter than the ones I took out, so I really should get it rebalanced. I suppose I could find a heavier pin and not deal with balancing, but since I’m going to be able to pull the engine now it just seems to make more sense to get the crank rebalanced to the lighter assembly. The heavier pins are going to cost almost as much as balancing anyway, so I may as well just take advantage of a lighter piston, right?

 

[Garys1969RR]

Thanks, I will do that, but it’s going to be a while before I get to that point though.
Yeah, I realize the quench isn’t ideal, but its about as good as I’m going to get. If I deck the block to get decent quench, then my static compression goes too high for my cam, so I’m not sure what other ways there are to do this.

Without a reverse dome piston, the only way to get good quench is with a flat top that comes to about .010 down from the deck. Then with a closed chamber head, and a .020 head gasket you are at .030 quench which has always worked well for me. But you're right, with 75cc E Street heads, you would be pushing the desired C Ratio over the limit.

 

[wyrmrider]

might be some tips in this thread
https://www.forbbodiesonly.com/mopa...y-engine-running-right.150738/#post-910943934

 

[400Magnum]

Thanks for the link! I’ll be sure to refer back to this if I have similar problems. It’s going to be a while before I get to this point though, I still have a lot to do before I’ll be ready to fire it up.