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Discussion in 'The Garage' started by big_truxx, Aug 13, 2005.
Wondering as i know summit sells SBC vortec but not BBC
stealership or summit has some aftermarket Vortec heads, they dont always list them but ya can call and ask them
ah i see. i wonder wht they cost. i know sbc are about $750 a pair.
Ya mean like these: http://www.sdpc2000.com/catalog/312...tec-BB-Chevrolet-Cast-Iron-Cylinder-Heads.htm
thats $860ish just for a pair of bare heads wonder if it would be worth it when everything else was added in
i would try to find a dealership that sells alot of engines. you usually can buy the cores for around $100.
or try a marine engine repair shop. they are always changing heads cams etc.
Welcome to the world of big blocks. Those big parts cost big bucks. You might find a set of clapped out peanut port 454 heads for $100, but don't expect to find any useable performance heads for less than 10x that amount.
Pre-Vortec stock truck 454's have abysmally low compression ratios. The full point jump with the Vortec heads, along with the better flow, swirl and quench, should help wake things up considerably. But yeah, to make a BBC really grunt can set you back some SERIOUS coin...
thats why i am thinking about just putting the larger valves and have a port job done on its stock heads less money
Installing bigger valves in a stock head will not increase performance unless the stock valves are restricting port flow.
The stock valves are probably optimal for port volume, flow and design, the biggest improvements to a stock head or any head for that matter would be port matching the intake side and polishing the exhaust side.
Stock heads are limited by the exreme angle the air must turn on it's way in and out of the chamber..........high-port heads are the ultimate solution but they are pricey and require changing the intake manifold to a high-port design also, Dart Iron Eagles offer a vast improvement in flow over stock heads and are a very affordable alternative if your serious about improving the breathing capabilities of your engine, the street version has a 308cc intake runner, 119 cc chambers and 2.25/1.88" valves and heart shaped chambers.
The intake/exhaust port flow ratio is the limiting factor in all stock heads and most aftermarket heads and should be the biggest reason for changing heads when desiring more performance.
If you are gonna run iron heads, find a set of stock 049 or 781 casting number, large oval port heads. Swap in 2.19/1.88's and they outflow the rectangle ports that came on the '70 LS-6. I found the set of 049's that I am runnin, on ebay for 100 bucks. After I bought them, I found 2 more local sets, one for $130, the other for $150.
If you wanna go hog wild, a little port work never hurts.
308 cc intakes are a rectangle port, not really suited to what your doing unless your over 500 cubes, or looking for 7000 rpm. I second the 781/049 recomendation. Or better yet would be some closed chamber oval ports like a 702 or 206 casting, for a little more compression. They are like 260 cc on the intake, the 2.19/1.88 valves wake them up with some mild porting. May end up costing you as much when your done as a set of merlins though. Which wouldn't be a bad choice, they work well and come complete for under a grand.
I posted in your other post to, but look at the link for the vortecs, it clearly says: "For use on 1991 and later Gen V and VI engines only."
That's funny, Dart lists them for applications under 500 cid and under 7,000 rpm.......
yeah vortec for the bbc appears to not be what i want/can do. weird as the sbc heads work great on the older blocks so i am told oh well.
so what would the 781 head be founf on? the 049? 702? 206? maybe someone can learn em what these heads are all about give me a little old school bbc head knowledge
I think 781's are about the most common I see, there on most of the 70's light pickups and I have taken a set off a mid 70's dually. Here is the link to mortec if you need to run any casting #s CLICK
Maddog, For comparasion, The big ovals are 256cc, peanut ports are 225cc, sure they will work but they will be soggy in the bottom end. I'm basing that on experience, not a vendors website.
cool beans and kudos (or beter yet many beers) to you for that link. is cool. think i got a casting # book around somewhere but that link is not misplaced and currently very useful. unlike the book lol which is misplaced i think i should find out what type of head i have or what they used in 89and see how it compares to others. if i leave the 454 in and rebuild, i could get away with a summit cam, headers and dual 3" exhaust. lol will have the tbi on top still. so maybe large valves and port job is unnecessary guess it all depends on cost efectiveness at the time of rebuild.
since i do not think i can see the casting #'s on heads till i remove some acess and all... and cannot tell exactly what i have... anyone able to tell me what they would run for head (#'s) on an 89 tbi 454 crew dually (scotsdale model 4.10 rear limited slip if helpful or makes any sort of difference)??
Dont know the casting #s but in all likelihood they are the small oval port heads(peanut port heads), that start runnin outta breath before 4000rpm. These are not performance heads of any kind. To see the casting numbers, pull the valve covers and you should be able to read the number down in between the rockers.
thats cool bro. thanks for the tip. cannot learn enough abotu chevies/chevy engines i bet u r right too. but i would think that a port job and larger valves should help hat head out lol
I'd guess 360 castings, that's the common peanut port for the tbi motors.
tanks thats what i would guess too. time will tell.
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