lets talk about heads

[MY85pontiac]

i am once again revisiting the idea of hopping up a 3.8 sans turbo and i'm considering doing a little port and polish on the heads.

i have a 4.1 intake i'm currently porting and polishing but i know the heads should be worked also for improved breathing. my goal realistically is to have a nice daily driver V6 with good low to mid range grunt. on the exhaust side i'm considering hedman headers but between the intake and the headers i need to work the heads. which side of the heads needs the most work? admittedly i know very little about the heads on these engines other than they're not very good as cast for performance. is it mostly a matter of smoothing out the runners or do they need a good hogging for what i'm intending to use them for? i do intend to shave the heads a smidgen to bump up the compression and the deck as well. i'm figuring about 9:1 would be good with a cam in the .450 lift range. also what about port matching? is it worth the time and effort? again it's for a daily driver not a race car but i want to get good performance out of the engine. i'm figuring smoothing everything out and not increasing runner size would help air flow and keep air velocity up and a cam with a dual pattern favoring the exhaust side would be good also. maybe the edelbrock cam as an example?

i plan on sticking with a qjet for the small primaries and may even use the CCC stuff if possible but if i change the cam i think that would really confuse the computer too much. i dont mind ditching the CCC stuff but i do like being emissions friendly simply because i'm an environmentally conscious person.

i might use a 4.1 instead just for the extra cubic inches, it couldnt hurt.

trans is currently a th350 with a 2.41 gear but i plan on putting in a 2004r and a 3.42 or 3.73 gear.

what about exhaust size? i'm thinking dual 2" all the way back.

 

[charlief1]

As far as the heads, you'll get more gain from doing the bowl area more than the ports themselves. That's where most of the restiction seems to be and it will create more flow than anything else. A cam like the Edelbrock one is a good update but going with a roller cam is the better idea. Much more expensive but works better.

As far as headers, see if you can find an old set of Hooker competition turbo headers. They look like NA headers but you don't need the crossover provided with them. I have a set if you want to see what I'm talking about. These are large enough to help you with the flow and then you can go with a 2.5" single which will help with more torque over all and not hurt the HP numbers.

Here's a couple of links of how to port the heads and the 4.1 intake. Hope this helps you out.

http://www.turbobuick.com/forums/before-black-non-sfi-tech/301108-little-head-progress-you-guys.html

http://www.turbobuick.com/forums/be.../281474-modification-4-1-4-barrel-intake.html

 

[MNcarbturbo]

What I did for mine was mostly based off of what my machinist said. The port enlargement has very little affect on flow. He cut a 70 degree slope into the side of the bowl on both the intake and exhaust side and then moved the valve seat to the outer side of the valve. It simulates the better flow of bigger valves but you can still use the stock valves. Then its as simple as taking a carbide and taking out the ridges and using sandpaper rolls to smooth the ports out.

 

[MY85pontiac]

thanks, i already had the 4.1 intake thread bookmarked, i needed one for the heads. i see how much work is put into the bowls and its a lot but i can see it needs to be opened up a lot. i'm guessing the 8445 heads are the ones to use more than other castings?

i have looked for hooker headers but the NA ones, not the turbo ones. i see the turbo headers on their site and they're like shorty headers but for 800 bucks??? that's a smidgen steep but they are ceramic but i dont need the cross over pipe and stuff. even the ceramic NA hedmans are only 700 bucks but those are full length, wouldnt those be better for torque vs short? the regular hedman headers are 200 bucks. that's over 500 bucks i could put into something else for the engine or the car itself. unless i can get a used set of the super comps for cheap...possible but not likely.

 

[charlief1]

thanks, i already had the 4.1 intake thread bookmarked, i needed one for the heads. i see how much work is put into the bowls and its a lot but i can see it needs to be opened up a lot. i'm guessing the 8445 heads are the ones to use more than other castings?

The 8445 heads are prefered because of the bridged water passeges on the end, but you can also find the same thing on the 293 castings. Not all the 293 castings have this feature though so you have to look at them to make sure.

i have looked for hooker headers but the NA ones, not the turbo ones. i see the turbo headers on their site and they're like shorty headers but for 800 bucks??? that's a smidgen steep but they are ceramic but i dont need the cross over pipe and stuff. even the ceramic NA hedmans are only 700 bucks but those are full length, wouldnt those be better for torque vs short? the regular hedman headers are 200 bucks. that's over 500 bucks i could put into something else for the engine or the car itself. unless i can get a used set of the super comps for cheap...possible but not likely.

You can find the hookers on evilbay once in a while and you might try posting in the wanted section for them. Long tube headers won't help that much and if you want a cheaper set you can get the pace setters. What most don't understand about dual exhaust is that if you're not going for high RPM and high HP duals don't help that much. Using a 2.25" pipe off the hookers and then joining them to a 2.5" will make more torque and not hurt the HP numbers more than 10 HP. The key on these engines is the torque they produce VS the HP numbers. Long tube headers may give you 10 ftlbs of extra torque but for the space it won't help you that much.

I do have a set of hookers with out the crossover if you're intereset in them and the nice thing about them is that they have really thick flanges so they don't warp as easily and seal better.

 

[usetaboost]

Id go for the cheapest set of headers you can get your hands on. 2-2.5 inch exhaust or even a 2.5 single. I would get another set of heads to get the work done on to reduce the down time. It may be worth it to find a set of used heads that have already been done. Use a thinner headgasket. If it was me I would just do cheap headers, intake, and the cheapest freeflowing exhaust you can get on the car. I wouldn't dump tons of cash into it, it's just a v6. I'd use the money you save to do 3.23 gears.

 

[MY85pontiac]

well it might be just a V6 but i plan on keeping this car for a long time still. i've owned it for 16 years and it's been a good car but i want something more than 110 HP. i dont want to drop a chevy in it as easy as that would be and i like V6's for some reason. i dont know why but i do. the current engine has well over 100K miles on it and while i did get the timing set replaced at 100K and it still runs fine i think the springs in the heads are giving out. i had a 4.1 in a 82 GP LJ and i liked the qjet on it.

i already plan on changing out the transmission and rear gear regardless of what i do with the engine and most likely i'll be doing those first but in the mean time i can work on heads and get my other ducks in a row as it were and prepare to do the engine after those are done. maybe a 4.1 short block with worked heads the 4.1 intake and a free flowing exhaust. upgrading the cam is just a thought, not definite but i want to look at my options anyway since i'll have plenty of time to mull it over.

it might be just a V6 but SBC's are just a V8 too. GM may have hamstrung my car with an underpowered engine but i dont blame the engine for that and not even GM itself. fuel economy and emissions standards have to be met but i can still get decent MPG with an OD trans while having a lower gear for more off the line fun at test n tune night at the local track. it's too bad they didnt do this with the n/a V6's back then. 2.41 peg leg with a metric 200 makes for a bad driver regardless of the engine. i just wish i had swapped it out for a 2004r instead of the th350 that sits under the car now.

i like V6 engines and i see nothing wrong with them and using them. my wife wants a cadillac 500 in the car and i'd like that too but that much torque will tear up a stock 2004r faster than i could get the car out of the parking lot at the transmission shop i take my car to. so i need to think more budget oriented. i already have a V6 and getting another one is cheap since nobody wants them so why not work with what i have and improve it? i can always get another car and put a cadillac 500 or whatever in it. like maybe a bonneville wagon...a real family truckster. i might not be playing with a full deck when it comes to engine choices but damn it i have fun with my engine and that's all that really matters. right?

 

[charlief1]

You sound like I did when I did my first one in the 80's. I did a ton of research on what needed to be done to increase the overall power and keep the reliability in it. Kenne Bell was still into Buicks and they had a bunch of goodies for them. I still have my KB 1 & 5/8" H body headers and I really don't want to get rid of them. I'm hoping to duplicated them one day but you never know after all.:biggrin:

 

[MY85pontiac]

since i got the car way back then i have been looking for parts to hop up the engine. weiand had an intake but its been discontinued, hooker had headers but those are discontinued as well. even pacesetter doesnt show them on their website now. edelbrock still carries their intake and cam and other intakes like kenne bell's are rare so my best bet was the 4.1. after reading your thread about porting a 4.1 intake i started doing the same thing to the one i pulled off the 4.1 before i sold the car off. i kept everything attached to the intake also because i figured just in case i decided to stick with the buick V6 i have a 4 bbl option later on and it can be emissions legal if need be. they have since stopped running it but they had an emissions program here and you had to test your car every year so intakes without an EGR wasnt an option for me. with headers they had to have a collector with a bung for an O2 sensor.

so since the intake has been sitting around for some years i'm looking for a 4.1 carb and doing the swap. its fairly straight forward and since i'm replacing the thermostat i only have to drain the coolant once not twice AND i dont have to worry about coolant draining into the engine but an oil change is still mandatory. the cooling system has already been drained and it's dry up top so that works in my favor i think for clean up.

about them headers you spoke of, how much would it take to have you part with them?

 

[charlief1]

I'll send you a PM on the headers.

 

[usetaboost]

why not just skip the n/a crap and install a turbo setup? If you are going to go through the time and spend money gathering all the stuff just as well get something that's going to be worth a damn

 

[ek02]

Charlief1 is right about the heads. I had a set of pocket ported heads with a 3 angle valve job on a 3.8 n/a. I got a set of 445 heads and ported the heck out of them, put in stainless 1.77 intake and stock size exhaust valves with a 3 angle valve job with my antique Black and Decker equipment, and filled the EGR and crossover passages with molten aluminum like Champion iron heads. Guess what? My et stayed the same as the with the pocket ported heads. I could not feel any difference in power. Without a turbo, ported iron heads don't make a big difference. Champion aluminum heads make a big difference, though. The valves are bigger and closer to the center of the cylinder for less shrouding by the cylinder wall, plus they use thin bronze guides and the port shape is better.