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Discussion Starter · #1 ·
Hi all, finally getting back on the t bucket build my dad and I started a couple of years back. We have pretty much everything figured out except for how I want to build the engine. The current specs are as follows:
1958 283 .030
305 #416 heads
Stock 305/283 internals (except with .030 pistons obviously)
Lakes headers
Stock 2004r
Ford 9"
Rear tires will be around 31" tall Firestone 750-16 bias ply

Now for my questions

1. If I run, say, the lunati clone of the 097
(30121009) what springs do I need to run? I reached out to lunati with no luck, and can't find any information anywhere

2. What gearing should I run in the rear end with these parts for good performance, I will be driving it basically everyday, but won't be doing too much highway driving

3. I have a Holley 1850-3 600cfm vaccum secondary, will that be too much/not enough for my engine?

I know only the basics of engine building, and have forgotten all I learned when I first started the project, so any extra knowledge would be super helpful and greatly appreciated.
 

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Shouldn't take any more spring than the stock LT-1/Z28 spring, a common medium performance stock diameter spring that nearly everybody makes a version of. Speed-Pro 943x was the old number I remember.
Howards Cams also has the copy of the 097 cam....their spring recommendation for it was the same deal, their copy of the LT-1/Z28 spring.
Howards #98212
Elgin RV-943X
Hi-Tech #2424

They are all in the range of 115-120 lbs seat, 300-340 lbs open. Just the variance in what installed height you set up at is all that changes the numbers....effective seat and open loads end up the same since the Duntov is only .400" lift..

Mechanical Flat Tappet Valve Springs-Competition Products.

From what I can glean from Lunati's crummy web site, it looks like the correct spring from them is #73943-16 ....('943' again)

The 600 cfm Vacuum Secondary will work well, probably need a spring change in the vacuum secondary to fit it to the light vehicle, and maybe a slight re-jet....but it's a good choice.

31" tires, I'd say probably 4.11 gear with that big tire diameter. I wouldn't go any smaller than 3.73.
 

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Discussion Starter · #3 ·
Shouldn't take any more spring than the stock LT-1/Z28 spring, a common medium performance stock diameter spring that nearly everybody makes a version of. Speed-Pro 943x was the old number I remember.
Howards Cams also has the copy of the 097 cam....their spring recommendation for it was the same deal, their copy of the LT-1/Z28 spring.
Howards #98212
Elgin RV-943X
Hi-Tech #2424

They are all in the range of 115-120 lbs seat, 300-340 lbs open. Just the variance in what installed height you set up at is all that changes the numbers....effective seat and open loads end up the same since the Duntov is only .400" lift..

Mechanical Flat Tappet Valve Springs-Competition Products.

From what I can glean from Lunati's crummy web site, it looks like the correct spring from them is #73943-16 ....('943' again)

The 600 cfm Vacuum Secondary will work well, probably need a spring change in the vacuum secondary to fit it to the light vehicle, and maybe a slight re-jet....but it's a good choice.

31" tires, I'd say probably 4.11 gear with that big tire diameter. I wouldn't go any smaller than 3.73.

Excellent information!! Thank you so much, yes lunatis website is awful, I ended up going with Elgin since a rep actually got back with me and recommended the same springs you did for their e-900-p cam.
 

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measure the combustion chamber volume piston dome height and deck height? You don't want to end up with 8:1 compression ratio...
What transmission are you using?
Tire size at 31" will make for tall gearing
750/16 truck tires are a horrible choice except for load carrying truck use.
 

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Discussion Starter · #5 ·
measure the combustion chamber volume piston dome height and deck height? You don't want to end up with 8:1 compression ratio...
What transmission are you using?
Tire size at 31" will make for tall gearing
750/16 truck tires are a horrible choice except for load carrying truck use.
Should be right at 9:1 cr.

Stock 2004r

What makes them terrible tires? I see them ran all the time on roadsters
 

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if the 750/16s are truck tires you will likely have 8 ply tires, these need to be run around 50# pressure. Immagine the ride quality?
.7 overdrive will give you a theoretical top speed of over 180 mph @ 5700 rpm. Not that the engine would have enough power,,,using a 4.1 rear gear
please show me your math to get 9:1 cr?
I would want a 283 around 9.7:1 for an engine with some cam in it
 

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Discussion Starter · #7 ·
if the 750/16s are truck tires you will likely have 8 ply tires, these need to be run around 50# pressure. Immagine the ride quality?
.7 overdrive will give you a theoretical top speed of over 180 mph @ 5700 rpm. Not that the engine would have enough power,,,using a 4.1 rear gear
please show me your math to get 9:1 cr?
I would want a 283 around 9.7:1 for an engine with some cam in it
Plugging my specs into a calculator online gives me 9.03:1 cr, with an .015 gasket. Any idea how I could get it any higher? Machine work is done on the heads so I'm sticking with the 416s for sure.

I'm not too worried about the ride, if it's so bad that I can't handle it then I will worry about it.
 

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.032
No clue, but it's a stock stroke 283 bored .030
6cc
With an .015" x 4.100" gasket and 58cc chamber I got right on 9.01:1 with those specs ^^^
Or 9.031 if you can come up with a .015" x 4" bore gasket.
Milling the heads .025" flat milled would get you up to 9.5:1. That's a common hot rodder performance hop up amount. It'll drop about 4-5cc's from the chamber.
Plus it will ensure the heads are nice and flat to go with the shim head gasket.
Doesn't sound like you had the block decked at all, not even a skim cut to make it dead flat...??
The shim gasket gets iffy when at least one side isn't flat.

I figured from the description of the build that the 7.50-16" tire was likely a street rod reproduction tire..... like all the traditional style rodders are using on pre-war cars?
 

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Discussion Starter · #12 ·
With an .015" x 4.100" gasket and 58cc chamber I got right on 9.01:1 with those specs ^^^
Or 9.031 if you can come up with a .015" x 4" bore gasket.
Milling the heads .025" flat milled would get you up to 9.5:1. That's a common hot rodder performance hop up amount. It'll drop about 4-5cc's from the chamber.
Plus it will ensure the heads are nice and flat to go with the shim head gasket.
Doesn't sound like you had the block decked at all, not even a skim cut to make it dead flat...??
The shim gasket gets iffy when at least one side isn't flat.

I figured from the description of the build that the 7.50-16" tire was likely a street rod reproduction tire..... like all the traditional style rodders are using on pre-war cars?
I have to have the valve guides worked anyways so maybe I'll have the heads shaved as well, I won't have any clearance issues with the bigger 305 valves?

I want to say I had the block flattened, but it's been 4 years since the machine shop so it's hard to say.

And yes the tires are the Firestone zig zag 750-16, they are 8 ply although I'm still not worried about ride quality.
 

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305 has a smaller bore than a 283
Eric what did you allow for eyebrows in pistons?
are the pistons rebuilder pistons sitting lower in the bore?
Per this info below from Post #10, I used those numbers Eerielayne gave:
Deck height has piston down .032"
Block given as likely stock deck, never cut
6cc valve relief

.032
No clue, but it's a stock stroke 283 bored .030
6cc
Rebuilder pistons are about all that is commonly available anymore for the 283, unless you buy forged custom.
 
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