A while back I read an article about vortec heads


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A while back I read an article about vortec heads

Post by markinnh »

I have a correction to the vortec heads article. The list that was on this forum was correct except there is also 305 vortec heads and although they are smaller in combustion chamber size they are still 194/150 valved heads. I bought a set of heads a few years back with casting number 125525520 I took these off a 1997 chevy truck with 5.0/305 after I read the article on here I didn't understand how you all say they are not vortec and yet chevrolet says they are so I did my own research and found out there are two different casting numbers for the 305 vortec heads and three for the 350 heads
with the exception of non factory installed yet factory sold. Basically this is because the 305 is not considered by most as a possible hot rod- able engine. I personally think the smaller piston would offer some reasonable hp and torque but without buying a gas station so to speak.
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Re: A while back I read an article about vortec heads

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The vortec 305 heads are prolly better than 95% of the stock heads out there from the smog years. There are better upgrades; but for a stock type rebuild, they'd be great.

On a side note, I don't like 305s, and have talked to many others with the same sentiment. I've had several, and don't see any diffenerce in fuel consumption but less power.

305 heads (or the whole engine) are ok for a driver, but not for a serious hi-po project. I'd take a 305 over a 4.3 though.

If you're gonna do it, do a 350, or a 400.
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Re: A while back I read an article about vortec heads

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http://www.chevyhiperformance.com/howto ... index.html
It's not a fair assesment to say that the 305 is not a viable performance engine. It all depends on what you want. I've said it before and I'll say it again........"Not everyone wants a 9000 RPM Screemin' Demon". I'm a big fan of the 305. I've built several and have been very satisfied with the results. More than 30 years ago I built a lowly 307 ( some of you older guys may remember it as Chevys first attempt at meeting the new smog rules ) And when everyone was saying you could never make a 307 perform I proved them wrong. At the time I had a '69 Nova. I redid the 307 that came in it and everyone of my friends thought I had replaced it with a 350. It wasn't about adding expensive highend aftermarket parts or adding nitrous. For me it has always been about learning how an air pump works and applying good sound principals to the build. Pay attention to the details. Do everything EXACTLY right. The 305 is a great platform to start with. \:D/
Last edited by Smiliesafari on Sun Feb 14, 2010 7:14 am, edited 1 time in total.
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Re: A while back I read an article about vortec heads

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Well since I have 2 305 blocks and one is a 1986 IROC block I figured why not build a stroker with a .30 over bore and a 400 crank kit and 305 vortec heads with a modified TBI on a 4 barrel intake. Most of the parts are from a 305 I built with a used crank that I basically took a mans word on when I bought it and it failed. so the cam, timing set up, intake and so on are still basically new since the crank failed with less then 3000 miles after the build. So I am building it again with the 400 stroker kit and the second 305 block. Now according to my research on this engine product I should see 300 hp at the crank. Now 300 HP is perfect for my little astro cargo van (which by the way has all the underpinnings from a 93 Safari GT)
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Re: A while back I read an article about vortec heads

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rlsllc wrote:The vortec 305 heads are prolly better than 95% of the stock heads out there from the smog years. There are better upgrades; but for a stock type rebuild, they'd be great.

On a side note, I don't like 305s, and have talked to many others with the same sentiment. I've had several, and don't see any diffenerce in fuel consumption but less power.

305 heads (or the whole engine) are ok for a driver, but not for a serious hi-po project. I'd take a 305 over a 4.3 though.

If you're gonna do it, do a 350, or a 400.
I agree-350 used roller engines are pretty cheap to get and with the same investment a better result without much difference in gas mileage.
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Re: A while back I read an article about vortec heads

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You are missing my point, I have the heads, the block the cam the chip and the TBI unit all for the 305 so if I wanted to go with a 350 all those parts are useless and I would have to buy them again for the 350.
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Re: A while back I read an article about vortec heads

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A 305 bored .030 and stroked an extra .77 (400 crank) will give you 334 cu. in. Very interesting combo. Long stroke engines are torque monsters. This sounds like a great motor for a 4000# van. The only holdup I see at the outset is finding pistons. Good luck. \:D/
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Re: A while back I read an article about vortec heads

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Re: A while back I read an article about vortec heads

Post by rlsllc »

Smiliesafari wrote:http://www.chevyhiperformance.com/howto ... index.html
It's not a fair assesment to say that the 305 is not a viable performance engine. It all depends on what you want. I've said it before and I'll say it again........"Not everyone wants a 9000 RPM Screemin' Demon". I'm a big fan of the 305. I've built several and have been very satisfied with the results. More than 30 years ago I built a lowly 307 ( some of you older guys may remember it as Chevys first attempt at meeting the new smog rules ) And when everyone was saying you could never make a 307 perform I proved them wrong. At the time I had a '69 Nova. I redid the 307 that came in it and everyone of my friends thought I had replaced it with a 350. It wasn't about adding expensive highend aftermarket parts or adding nitrous. For me it has always been about learning how an air pump works and applying good sound principals to the build. Pay attention to the details. Do everything EXACTLY right. The 305 is a great platform to start with. \:D/
I agree with you 100%, and would only like to add that doing the exact same work on a 350 or 400 would give you more back for your money. That's my only point. As far as a small displacement build, there are some combos that work better than others. The Chevy 307, 305, 267, etc are examples of not so good. The 283, 302, and 327 were on the other side of the equation. I still feel that displacement and vehicle weight are to be considered, a hot 283 in a 6500 lb dually isn't gonna cut it, lol.


And Mark, I do see the logic in building what you have (the 305 stuff) instead of buying it all again, and agree that the outcome will be interesting. I like to "run what ya got" too. Rock on, and good luck.
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Re: A while back I read an article about vortec heads

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Great find, Mark. I'm going to be watching this build. I really like doing things a bit different. Keep us posted.

Roy, You are correct in that weight is a primary consideration. A small cube engine in a heavy vehicle is strictly utility. I think you'll agree that before you start building, all of the parameters of the final application should be addressed. It's key to success. \:D/
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Re: A while back I read an article about vortec heads

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rlsllc wrote:The vortec 305 heads are prolly better than 95% of the stock heads out there from the smog years. There are better upgrades; but for a stock type rebuild, they'd be great.

On a side note, I don't like 305s, and have talked to many others with the same sentiment. I've had several, and don't see any diffenerce in fuel consumption but less power.

305 heads (or the whole engine) are ok for a driver, but not for a serious hi-po project. I'd take a 305 over a 4.3 though.

If you're gonna do it, do a 350, or a 400.
ive heard many a bad thing about the 400's too though. they took a good block and went too far, they are known for cracking due to being bored out too much. i actually have a 400 in my 77 chevy camper van but i dont race the thing around or anything and it has extremely low miles, but if it were up to me it would be a 350. and that is prolly what i would build up if i were in the market, or maybe a 383....
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Re: A while back I read an article about vortec heads

Post by rlsllc »

GnarliSafari wrote:
rlsllc wrote:The vortec 305 heads are prolly better than 95% of the stock heads out there from the smog years. There are better upgrades; but for a stock type rebuild, they'd be great.

On a side note, I don't like 305s, and have talked to many others with the same sentiment. I've had several, and don't see any diffenerce in fuel consumption but less power.

305 heads (or the whole engine) are ok for a driver, but not for a serious hi-po project. I'd take a 305 over a 4.3 though.

If you're gonna do it, do a 350, or a 400.
ive heard many a bad thing about the 400's too though. they took a good block and went too far, they are known for cracking due to being bored out too much. i actually have a 400 in my 77 chevy camper van but i dont race the thing around or anything and it has extremely low miles, but if it were up to me it would be a 350. and that is prolly what i would build up if i were in the market, or maybe a 383....
Stay away from factory 4 bolt main 400s. Those are the weak blocks.

I've seen many built 400s live, and a few die. The trick is to find a block with the bores evenly spaced. There is a way to check it but Im drawing a blank on what it's called, maybe sonic testing? You can find good ones if you look. As a rule, avoid anything over .030 on a 400.

The biggest trick with 400s is the cooling system, and running a 50/50 antifreeze mix. You really need a good radiator, properly shrouded fan and a 16lb cap, and running a 180* thermostat with a couple of holes (like 1/8") drilled in it. Better have an overflow reservoir also. 400s are picky about this stuff because on the "steam" holes in the heads and block. This was told to me by a guy who was building engines since the days of the flatheads. He built one for me in the 90s, it was a screamer and never overheated in a 1985 Monte SS.

I have a buddy with a 400 that is bored .060, flat tops, and runs like a scalded dog. It never goes over 180* F.

I have also heard of 400s that overheat no matter what you do. It's just hard to tell.

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Re: A while back I read an article about vortec heads

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The cool thing about building such a small bore engine is that a cam that would be mild in a 350 will be alot of cam for the 305, according to an article in popular hot rodding. so my cam should work well with my build and the chip I had burned for my 305 build last year will still work. The chip was burned for egr delete because of the vortec heads and for the home modified TBI unit. The only thing I am unsure of in this build is whether I use 350 injectors or 305 injectors. I have both so I guess I will simply do the trial and error.
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Re: A while back I read an article about vortec heads

Post by 1Gary »

Hey Mark,

On a Hot Rod forum I look at,there are a number of threads that stated Vortec used heads are prone to cracking in the seat area.They are saying guys have checked a number of sets of them before finding a good set.Just passing the info on to you for a heads-up.

Looking forward to the build.Please keep us updated.
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1999 Sonoma 4.3 5 speed-Rufus
1989 Astro-Ole Yellar cancelled-still selling off parts
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1982 Winnebago single rear wheel-Chevy 350 Scraped 1/28/13-broken dreams......


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Re: A while back I read an article about vortec heads

Post by markinnh »

I had mine shaved and they were crack checked prior to that but thanks for the info
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