400sbc vortec heads?

[3r!c84]

hey guys let me tell you my set up first. 400 sbc 2 bolt mains. stock bore. stock crank. flat top pistons . crappy 76cc truck heads. with 1.6 rollor rockers. better springs. msd hei dissy. edelbrock performer EPS Intake. 1 inch 4 hole plastic spacer. holley 750 vac secondarys.elgin cam split lift .503 .510 (forget the rest lost card a whileago..) th350 with a shift kit. stock converter from the 305. 10bolt rear with 3:42 gears. runs 13.9 as it is. in a 84 swb


im at the point i want to toss thos heads

ive looked up and found this build :
http://www.popularhotrodding.com/eng..._block_engine/


making 428hp and 525tq. with the vortec heads.not to shabby

so i know i would have to change out my pistons since i have flat tops .

i found a guy on craigslist with a set of:
https://www.patriot-performance.com/...productid=206&

and edelbrock vortec air gap intake. and rollor rockers (unknown size.)
all that for 500..

so what should i do?

[3r!c84]

84 c10 pbir - YouTube

[Captainfab]

Those Patriot heads, intake and rockers is a pretty decent deal, depending on the condition of the parts. I believe they also flow a little better than the OEM Vortec heads.

[3r!c84]

i believe so. also they can handle more lift then the stock vortecs.

[mud.man.rj]

So if you use the Vortec's on the 400 don't you have to drill steam holes in the Vortec heads, should have to right, just like any head used on a 400 Small block or could have overheating issues at slower/cruise speeds.

[3r!c84]

yes sorry for got to add i would have to have them drilled for steam holes

[3r!c84]

the flow charts of stock and Patriot


edit!!!!

wrong one

[3r!c84]

this..

[400smallblock]

im not trying to pee on your intended setup, but with those heads and flatop pistons your compression will be at or over 11:1. i double checked on summits website. they have a compression calculator. i sed sotck boe/stroke,5 cc for eybrows in pistons,.015 deck clearance and .040 gasket and 64 cc heads. came up with 11.1:1. i passed on a .030 over 400sbc off craigslist with flatops for this very reason. i want to put vortecs on it.i didnt want to run that high of compression on the street and pay for high test gas and additives to keep the engine from detonating.just my .02.good luck

[3r!c84]

very good point. i would have to be changing to some dish pistons. since i would like to run on pump gas (93or91 whatever each station has) just was wondering what size dish and would it be worth it. since i need to change pistons and rings..

[mud.man.rj]

I did the same at 11:1 copm on an engine lately, a daily driver, had to be a bit picky on the timing but runs on 91 octane and works just great, the reason is the chamber is very efficent compared to the first Gen head type. Seems to burn the fuel mixture very well, not detonation and is in a 3/4 ton 71 Gm 4x4 running 38" swampers with a 3.73 ratio. Couldn't do it with the old style heads and that comp. ratio.

[3r!c84]

yeah it can be done! but just justifying if its worth it. or just wait to find larger chamber heads that flow just as good or if not better..

[mud.man.rj]

No stock head will outflow the Vortec's, only an aftermarket, but paying more. Actually I just did another engine in a Corvette and bought Edelbrock (alum) RPM heads and paid $630 a cyl. head complete, worked out very well besides being new they are lighter being aluminum. Can get 3 diff chamber sizes too first first Gen. Gm.

[3r!c84]

yeah thats 1200 for heads lol no thanks... id go patriot heads if i was going new alum heads. hear good things about them and cheap.. but was just looking into vortecs but hate the small chamber thing

[AustinScott]

I have these heads & intake on my 327..... it's a fun ride.

here is one

Patriot heads and older blocks

[BIGBLU 72]

I run a flat top 406 with vortec heads with a cam really similar to yours (.510 lift Voodoo). i had everything ballanced and the heads and block decked to just true them up. i went against the conventional wisdom of cutting down the spring seats or whatever and decided to run the LS6 yellow beehive springs with the correct Comp retainers and locks. ive spun the thing to 6500 rpm and no issues (i know someone will disagree) here in East Ky i can get 93 octane and the truck runs just fine! a real tire fryer! no clue what my numbers are but its responsiveness feels identical to a 396 truck that we used to have. FUN ENGINE TO PLAY WITH

[3r!c84]

got any pics or any more info on this motor?

intake
size flat tops
flattop with releifs
exc..

[BIGBLU 72]

.030 Speedpro flatops w -4cc reliefs (don't quote me on that one) I'm running the GMPP vortec duel plane Intake (same as Performer RPM) I did go w a slightly thicker head gasket .041 maybe? Topped w a 680cfm Quickfuel
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[3r!c84]

okay any guys on compression ratio?

[BIGBLU 72]

My engine guy said I was right at 11.1 w my set up. Let's say it doesn't like 89 octane at all
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[3r!c84]

yeah we have 91 everywhere. and someplaces have 93. i want to run pumpgas..

[Captainfab]

What you really need to do is gather all the necessary info, and calculate your dynamic compression ratio. That is what is one figure that is going to determine whether or not you will be able to run pump gas. You will also need to keep the engine cool, the intake air cool and you will need a good ignition system.

[shortbed70]

I would say go for the heads. I run tem on my 361 sb and wow! I just put on a Holley street dominator intake and this thing runs great. If you run a old style intake use felpro gasket 1206!!! Trust me! Also for the record and my experience these heads are more similar to the GM fastburn... These things in hotrod magazine made the most power out of 7 competitors!!! Great heads but have a few small former issues on intake bolts...
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[3r!c84]

with a compression calculator on the internet i got this.
but this some dont count in the fact of piston dish or dome ?


Bore: Diameter in Inches - 4.125
Stroke: Distance In Inches - 3.75
Head Gasket: Thickness In Inches - .039
Cylinders: Number of Cylinders - 8
Cylinder Head Volume Number in Cubic Centimeters (cc) - 64

With Compression Ratio of - 11.319




thats to high for pump gas...

[mMad Dawg]

Just wondering if it would be possible to build a 406 to run on propane. I've been told the octane rating is higher than pump gas, and cheaper too.