school me about heads. Power increase idea

[4X4HIGH]

The only way to tell is to measure them. GM used 2 different sized valves in the same casting number heads so you must measure them.

 

[RootBreaker]

i prefer torque over horsepower, horsepower is overrated unless youre seriously racing track

imho


good luck

I agree... I was going to go with a .474" lift comp cams xtreme cam.... I also put vortec heads on.... now knowing vortecs can handle up to .480" lift max.. I knew I was going to be close.... but talking to the summitracing guy.... we figured the cam to start making power at 1200rpm's and up... so I fugured drop to the smaller cam... .454" lift and it is idle and up for power... so I lost some HP and torque but that is ok with me....


these motor mods can be expensive and make you question why you didnt get a new crate motor....

cam = $255
Intake = $120
water port blocks = $20
heads = $200
gaskets = $75
oil and filter = $20
antifreeze = $20
___________________________
total $710

now if I wanted to have the head work done...
remove push in studs and tap and use screw in studs, cut valve guide, make room for larger springs (doubles) = $255 plus springs $65 = $310 that I didnt want to spend so I said screw it.....also helped me decide on the smaller cam too

 

[ZooMad75]

So how does it run with that cam and the Vortecs?????

 

[RootBreaker]

So how does it run with that cam and the Vortecs?????

well funny you ask.... Dont know if you read my posts... i had a delema where I couldnt go more than 1/4 throttle without it bucking really bad... well the guys here recommended me to goto the parts store and put a 1991 caprice plug next to a 1996 tahoe plug.. well I did that and the tahoe plugs have MORE threads... so i replaced the plugs... timing then was off and so is everything else.. I need to re-adjust the timing and carb... but once I do... I will let you know....


all in all... my truck was underpowered... I had to FLOOR it from a redlight to get moving.. now that 1/4 throttle is SOOOOOO much better....

before I could drop the clutch at a light and not get knocked back in my seat... shift hard and barely give a head jolt... well not barely IT DIDNT!!!!

after I put the plugs in and just grabbed the distributor... and turned it so timing isnt accurate yet... I dropped the clutch and it threw me back.... banged gears and it threw me all over the place


I can actually feel the front walk up (not like a wheelie) but my softride 6" leafs sag down to 5" and I can feel it lift up... in L, 1 and 2nd gear.....


it is supposed to rain all weekend plus I am putting in hardwood floor in a room im redoing for our new baby on the way.....but if I get time to get out. Im gonna take out the camcorder and go into the woods for a bit....


oh yeah also because I did cam, heads and intake I feel ALOT more power but cannot contribute to say what was the best mod for the power difference......

 

[ZooMad75]

Sweet. I probably saw your other post on the drivability issue, can't remember. So you ended up putting the earlier plugs in or the later plugs? Sounds like it's close though. Like I said before, I'm getting ready to do this same swap on my dad's Nomad and want to make sure I got my bases covered. His 327 was pretty strong as it sits with the fuelie heads and solid cam, so I don't think we are going to see a major bump in power (same CC size so same CR) but we should get better driveability, smoother idle and better fuel economy (still with no loss of power).

I'd like to know how it runs once you got the timing and carb dialed in.

 

[RootBreaker]

So you ended up putting the earlier plugs in or the later plugs? .

put the 1996 plugs in and viola

 

[uberbeans]

I just replaced the heads on my 383 with edlebrock aluminium. I had really fresh stck chevy heads with 78cc combustion chambers 1.94/1.50 size valves. There was nothing wrong with the heads and I only had about 5000 miles on them. They are pinned and there is some porting done. These are by no means a baddass set of heads but they are pretty fresh. Unless you are running drag racing or lots of high rpm (sand drags/mud pits) having the 2.02's and 1.60's are of no use to low rpm operation. My new heads have these bigger valves but thats not the reason I bought them. I bought them for the bump in compression and the fact that aluminum heads allow you to run a higher compression not to mention that they are about 40 lbs lighter each. The way that the edlebrock guy explained it to me is that aluminum heads dissapate heat a lot better than iron an as such you can run about a point of compression more than with iron on the street. Very helpful if you are concerned with running pump gas. My 383 because of the stroker design inherently has a higher compression right of the bat. With my old 78 cc heads I was still close to 10 to 1 compression and with the 64cc heads I am close to 11 to 1. I am still running Premium but I don't detonate even with a trailer. I whole heartedly endorse aluminum . It is expensive, though. I agree with the above posts when they say compression is more important than valve size. There are ways to modify lower compression head to bump them up like shaving them. I have these iron heads that I will let you have for trade or really cheap. Like I said before they have 5000 mules on them since they were fully rebuilt professionally (ie-not me). They have 78cc combustion chambers 1.94/1.50's, pinned rocker pivots, slightly ported and polished. They ran great. They are a sure thing instead of a questionable junk yard find. I'll let them go cheap or trade because I have absolutely no use for them. I don't have the casting numbers with me (because right now I am screwing off at work) but I could get them for you this evening.

 

[roadnotca]

Ditto on the Edelbrock heads. I just started tryout on the middle grade gas, seems to work fine. I had built enough engines, this time I said WTF and just bolt them on.