|02-02-2013 08:40 PM|
|vinniekq2||hogg what do the chevy 291s and 292s flow? after porting what do the 292s flow. which is a better casting, 31s? or 292S?|
|02-02-2013 02:08 PM|
If you want a better flowing GEN 1 head, you have to go to the aftermarket.
Lift limitations are fixed by springs/retainers.
They do require a dedicated intake.
If you want to take a production head, slap it on a shortblock with the goal of making the most power/torque, the head that will do the job is the Vortec L31head.
Not only are they great heads, GM never installed a better GEN 1 head on any vehicle they ever made, car or truck.
|02-02-2013 12:26 AM|
|vinniekq2||650 double pumper is a very good performance carb for small or mild engines.I use 750s as a minimum usually|
|02-02-2013 12:19 AM|
|73nova350||i have a edelbrock 600 carb with vac secondaries and i also have a holly 650 double pumper with mechanically secondaries, which one would be better with this setup|
|01-27-2013 05:44 PM|
|vinniekq2||how about,vortec L31 cast iron heads are very good for moderate performance applications. Just so as to not make it look like vortec heads are just great heads.They have quite a few limitations.|
|01-27-2013 05:20 PM|
So, again, here's the way to say it.....
L31 Vortec heads are the best flowing SBC PRODUCTION cast iron heads that GM ever produced.
Hang in there, it gets easier......
|01-27-2013 02:25 PM|
|camaro355||find a set of vortec heads they are the best cast iron heads gm has with a valve job and port work and bowls blended these heads are pretty impressive|
|01-25-2013 01:29 PM|
what would be the best heads
I wouldn't think there is anyone that can tell you what size combustion chamber to purchase without knowing the piston brand or the volume of the piston. (Flattop-5cc dished-18cc). While the heads are off measure the distance from the top of the block to the top of the piston. Write it down and keep it handy because you will need it to figure your quench, head chamber volume, and compression ratio.
|01-25-2013 10:55 AM|
|73nova350||thanks for all the info guys, any idea on the power gain i would get out of this?|
|01-24-2013 09:24 PM|
Lots of good suggestions here, but at the end of the day research is your friend. The dart SHP'S seem to be somewhat dissapointing, the brodix IK's have a great rep for the most part, the kmj is procomp stuff, not saying its good or bad....just saying do you research. I went with the Pro-Filers because they are price wise comparable or cheaper then the brodix or dart, yet being compared with, and some claim better then a much higher priced AFR eliminater head. And there was enough info out there to make a somewhat educated desicion. And when I E-mail a company at 10pm at night hoping to hear back the next day, and get a response 10min later. (Speier Racing Heads) I'm happily surprised. Unfortunately he was out of stock at the time, but still answered my questions, and still reccomended the pro-filers.
Some food for thought...some inane arguments, but when its a fight over which is better, the pro-filer or the afr, you know your in good company either way.
How to choose the correct cyl head - Page 2 - Chevelle Tech
Profilers 195 vs. Afr 195 - Page 2 - Team Camaro Tech
Air Wolf 220 Results - Chevelle Tech
|01-24-2013 08:41 PM|
|496CHEVY3100||Check out a site called ASA Performance in Columbus Ga ,also listed as ,abad71camaro.same buisness he has aluminum sbc heads 64cc 200 or 220 runners Complete and assembled For Under $800 with free shipping.lots of locals run these ,I donot mine is a Big block with custom aluminum heads ,Good luck|
|01-24-2013 07:50 PM|
|01-24-2013 06:55 PM|
Assuming stock bottom end, you may be as low as 8:1 comp right now....with 76cc heads. Small Carb, no comp, bigish cam, all of this spells dissapointment. If your leaving the bottom end as is, then get heads with a 58cc chamber, run a 0.015 head gasket, get yourself a 750 Carb, and watch as all of it comes together and makes far more power then you currently have. Call this guy. Speier Racing Heads and tell him what you have, and want to accomplish. His prices are excellent, he is available all hours of the day...and will tailor the heads to your combo.....ie: 58 CC chambers for 10:1 compression.
And there you are.
|01-23-2013 02:49 PM|
Stock 350 iron heads that you had 1.94 intakes put into, what is this? Unless the heads were off a heavy duty/industrial engine they came with 1.94 intakes. What is the head casting number?
In selecting the chamber volume for new heads you need to understand the pistons you have. Most pistons have a circular dish, these are not very good for performance nor efficiency regardless of the head used. Other choices that can be there are D dish, flat top, or dome but these don't typically show up in OEM motors so unless this has had some custom bottom end work it's not likely to have these kinds of pistons. So far as pistons go in the 350 flat tops or D dishes work the best and are generally seen with a small chambered head say 58 to 64 ccs. Chambers are best when shaped and generally proportioned around the characteristics of the L31 Vortec. there are aftermarket large chamber heads that use much of the L31 technology but these are really for blower motors or big inch small blocks, not that they couldn't be used in a 350 with domed pistons. Another critical item is the thickness of the head gasket and the clearance distance between the piston crown to the block's deck. These two things control the squish/quench clearance where in combination you want to hit about .040 inch. With a small chambered aluminum head with an unmilled deck, where you can get into trouble is with a thick gasket often specified with an aluminum head, in tis case with a .025 inch deck clearance and a .053 gasket you can end up with a .078 clearance which greatly reduces the effecctivness of squish quench. So you've got to keep an eye on these dimensions and look out for a thin head gasket that is also compatible with the aluminum head. The issue here is that the aluminum head expands and contracts more than either the iron block or steel gasket, so it rubs on the gasket which wears grooves into the softer aluminum. The best and longest lived gasket needs to be made to accomodate this, multi-layerd steel, graphite faces, and composition build ups are used and have different thicknesses, a simple steel shim would become a problem in street or mixed street strip service with the aluminum and iron sandwich. You can get away with a steel sim in this type build up for race only where the heads are just considered an expense item to get into the winners circle, which means it works, but not forever. A zero decked block is probably easier to work from for the street ot street/strip as it allows a thicker mulitlayer or composition gasket to be used which is easier on the head's mounting face so the sealing and the head lasts a long time.
As you can see there are a bunch of things to keep track of all the while realizing there's more than one way to skin this cat.
|01-23-2013 12:55 PM|
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