Inliners International Forums General Discussion Engines 250 Chevy cyl. head mods

I think I'm going with 1.94" intake valves and milling about a .050" off the head for a little extra umph. Anyone else done anything similar and were the results OK?
Thanks

It depends on what you want for the finished product.
.050 off the head for a street engine is a lot. I prefer to take .030 for street, you start to sacrifice strength with more cut than that.
For the valve size on a 250, 1.84 will provide plenty of flow for street use and be able to really shine when pushed harder. The 1.94 valve will need some chamber work to help get the flow to work properly.
So, I am saying the 1.84 is easier and will need less work for 95% of the flow the 1.94 will give.
Bolt in lumps will be a nice addition and give another honest 10% flow. Tom

You can install a 194 CI engine cyl head to raise the compression. Its a direct bolt on depending on what year 250 you have.
Track testing ,& racing against my friends car, it was the fastest naturally aspirated combination I ever had using the 194 cyl head. Mid 13's in the 1/4 mile.
Also, Mr Hotrod6 set an ET & MPH record w/a 194 cyl head, his MPH record still stands today.
IIRC, I milled .050- .060" off the 194 head & it was my daily driver w/12:0 compression . 230 PSI of cranking pressure. Pump gas 91 octane.
What year engine is your 250?

1.84" intake & 1.60" exhaust valves & some bolt in lumps http://www.t6racing.org/id4.html would work very well. Relieve the chamber wall some & bowl work.

I had 12:0 compression ratio w/307 SBC flat top pistons & a milled 194 cyl head.

MBHD

I'm using a 250 head with a .030 cut and 1.84 valves which gives enough a compression boost and adequate flow to support a 4bbl. carband Cpomp CamsCL61-246-4, which is a 280/280 duration cam . The dyno tests that TLowe ran showed the 194 head caused a loss in power in stock form.

I think I will go with the 1.84" intake and 1.60" exhaust with a little less milling. I want to run pump gas. The block is also zero decked.

I,D JUST DO A CLEAN UP PAS ON CYL HEAD SURFACE, 1.84/1.60 VALVES AND GO WITH FLAT TOP 307 PISTONS. I-6 ENGINES ARE BAD ABOUT CRACKING CYL HEADS AND THE LESS YOU CUT THEM THE BETTER OFF YOU ARE . JMO
BOB

the intergrated was more prone to cracking then the other heads.and mostly due to over heating then anything else.It's just like the low deck motors were more prone to cracking at the #1 cyl right over the water pump,compaired to the tall deck 292 which didn't due to a much thicker block (being taller)
And if you run the 307 pistons and the 194 head you should be around 10.1 Give or take when milling the head or the block.

I'm using standard pistons.

with a stock dish at best you'd be around 9-1 give or take a little either way. And this all depends on what is milled off where and how much.

IT WILL BE CHEAPER TO JUST GET A SET OF 307 FLAT TOP PISTONS COMPARED TO CUTTING YOUR HEAD OR BLOCK. 307 CAST PISTONS ARE CHEAP AS KNOWBODY BUT US GUYS USE THEM HARDLY.

EXAMPLE

http://www.ebay.com/itm/Chevy-307-Sealed...=item4cfe07edb8

The ad does not say if they are over sized or for a standard bore.

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Available in .030, .040, .060 oversizes
•
1.655" Compression Dist

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5/64" 5/64" 3/16" ring grooves

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Stock length rods, press fit

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8.7:1 Compression Ratio 1968-72

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8.3:1 Compression Ratio 1973

MBHD

hum i guess i missed it. thanks

This is a 250 'we' have been working on, (Hawkins Custom Machine Shop).
2 more are already in the works with 'other' mods!

Enjoy:
http://www.facebook.com/video/video.php?v=387321371284995

Gotta love those 6's when they 'rap' up like that!!

Sorry, but I dont want to join facebook.
Got another link?

MBHD

I don't have Flash Player either.

Another link would be helpful.

Thanks,
Stu

Timmer:
I like it!

Paul..aka Xerxes