Thread: Desperate for more info on using 305 heads on a 400

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Hi, i'm really really curious how 305 heads will work on a 400 small block, i've already opened up the ports abit, i still want to polish the runners etc... they're 416 Castings, 1.84/1.5 valves 58 CC chambers. If any of you guys know or know someone who's done this before let me know... if i dont find anymore info i'll try them out, if they're gay then i'll get better heads... Thanks...

everything that i have ever heard on 305 heads even ported and polished are that they just cant breath enough to feed your 400 try some vortech heads {dont forget the intake specific to these heads }instead

Well i can use a pair of 993 Heads, but they got 76 CC chambers,
and the pistons i got, they arent quite flat top, but arent quite dished... i doubt i'll have any compression with thoughs heads...
i'll probaly use these heads, if they dont work out very good, i can always swap and get a better pair... i'd like to get a pair of vortec heads, theres a pair selling for 550 Canadian out here, but i dont got the money for em right now, i gotta focus on getting my engine running and int he chevette before i get anymore goods for the engine...

Hey Trent!

This is Mark from Mission BC too. Now that's a qoincidence! And we both got vettes
with 400s! Except that mine is a corvette!

I drilled the steam holes in 202 camel hump heads. All you have to do is use the gasket as
a template and mark where the holes should be drilled. The holes in the thick are easy and
aren't angled. The top skinny ones are a little bit harder though. I made a jig to get the
correct angle but you could eye it. For the angle use a good punch or else your bit will just
slip. Set your press at an angle if you have one and this will ensure all are the same and
don't hit the ports. I made a jig by finding the angle inside the previous heads. I would give
you my old heads if I didn't port too far and hit the water jacket.If I were you, I would try
and find some 882 casting 76cc 1.94/1.5 heads for your 400 as they breathe a lot
better.There are tonnes of these heads around. Try LORDCO machine shop. They have
tonnes of heads. I was lucky enough to find my 202 heads in the buy and sell for 350$
with bronze guides and 64 cc chambers. My 400 is going into my 74 stingray that I got for
an awesome price of 2300$ Can.. E-mail me with any questions about the holes at
markismcmoody@hotmail.com
See you at street-legals! Maybe we can race our vettes!

i have a set of 58 cc heads im going to use on my 350 with 2.02 1.60 valves i have a set of bare 1969 heads from a350 for sale make an offer 248-335-7274

dude, would love to buy your heads off you. but you live way in michigan... i live in BC, Canada ( west coast) shipping would be exspensive...

I am told that the best head for a 400 if you must run stock heads is the 305 Vortec head casting number 12552520. It is the same as the 350 Vortec but with smaller chambers.

f.y.i. Some of you may allready know this, but using 305 heads on a 400 mill will work but it won't perform. The only time I would use this is if I was stranded in the desert and I needed a head, and the only thing there was is a 305. If one where to take one of the cylinder volumes of a 400, and divide that by 57(chamber size)plus the chamber itself (1), you would find the compression ratio. Now, that's pretty hi compression for a chamber with a poor burn rate and rotation pattern. Yeah, it will work great, just don't turn it over 1850 rpm! Oh' yeah 110 octane is $3.50 a gallon. On the street, why not just run a good 10/1? Oh yeah we're runnin out of good 400 heads! BB

once, and had some decent results.

I put a set of truck (don't remember the castings) 305 heads on 1 383 with flat top (four eyebrow) pistons.

We ported and poslished the snot out of the heads.

This was in my 85 Franken Vette, back in 94 or so.

Results:

I went from 13.8 in the quarter to 13.01
Gas mileage went up by 4 mpg on the hwy and 2 mpg in town
My 60 foot went down .4 and my 1/8 mile really improved (that was my biggest gain), but I don't remember that number.

We went with 1.94/1.5 valves on a fairly mild crane 2040 compu cam and 1.5 full roller rockers, headers, and 3.07 rear gears on a 700R4 trans.

I drove the car with the 305 heads for three years. Sold it to a guy that drove it another year that way until he submarined the car on a flooded rod and bent a rod.

Long story short...it worked for me.

However, my fuel injection with the use of the knock sensor kept me safe, and I had to run premium gas all the time.