Understanding Cylinder Head Porting and Selecting a Camshaft to Match

[@firebird70]

I really like your topics, specially when being pontiac based, keep’em coming

[@LSxHunter]

If there's anything You'd like to see, let me know! Always happy to help!

[@firebird70]

@@LSxHunter i'd like to see if you could crush some of my specs in your program, are you on fb ?

[@LSxHunter]

@@firebird70 facebook.com/lsxhunter - Feel free to shoot me a DM

[@vhp454]

We built a 468 Pontiac. We used an All Pontiac block, Eagle rods and crank , Ross forged pistons, Kaufman 310cfm heads, Kaufman North wind intake, Comp 284h cam, proform 850 carb. This combination has made 610 hp max at 5900 rpm , torque max was 655 at 4600 rpm, this engine did make 500 ft torque at 2800 to peak. We have recently got more customers asking for flat tappet hydraulic cams more than rollers

[@hollyburkhart2279]

you are the Pontiac Guru. I enjoy your videos you break them down for the average guy

[@justanobserver530]

Really good video and it certainly matches my experience! I don't know how you feel about the edlbrock or kaufman heads but my current engine build I'm going with the kre specifically because of what you cover in this video. Keep the videos coming, there are many more Pontiac people that would learn something from videos like this!

[@stukksmith122]

Hey Pontiac brother I'd like to see you delve into David Vizards intake valve opening formulas for cam selection.. My understanding is it's to open the intake in relation to when the piston starts pulling to maximize our efficiency. LSA=128-(CID/#ofcylinders/valve diameter x.091). In his experience this is the place a cam recommendation begins . We may see reserse split duration actually better for max torque production but we faithfully use these off the shelf grinds. Come on bro maybe you can prove them wrong. Thanks Pontiac Stu

[@rogerharrelljr1935]

I’m having a set of 6x-4’s going on a 406 with a Spotts Performance HCP01 cam, factory pistons, but with ALOT of work!, good pistons, good crank, edelbrock performer, Holley 800 spreadbore. Marty is porting my 6x-4’s and recutting the exhaust seats for 1.77 exhaust valves. I’m just wondering if I need to switch to something more like the RA4 cam. Th400, 10 bolt with 4.56 gears. (1/8th mile car) eventually going with 3.42’s in hopes of running the 1/8th like a glide, just using 1st, shifting once and going through the lights in second at about 57-5800 rpm. Marty is porting my 6x’s to the max amount that my motor will need. He’s gonna put them on the flow bench before port work, then after. I’m soooo looking forward to what it comes out like.

[@markburkey6371]

Thanks for the knowledge sir!

[@LSxHunter]

If there's anything you'd like to see, let me know! Always happy to help!

[@jesseowens1492]

Had a shop in Kent, Wa offer to do my pristine X4 heads needing seats, port/polish and angle job. For $3k. Only $600 more than new Edelbrock aluminum's.

[@swappedoutZ71]

Hey I bought a shelf cam designed for stock motor trucks. I have ported heads and ported manifold and want to go slightly bigger on the cam. What is a good ballpark figure on what I should increase duration and lift to? Being that I can support more flow than what my current cam is intended for. Not asking you to magically come up with cam specs but just asking how much would you "add" to the cam when specing a cam for stock top end vs fully ported top end. I'm thinking increase duration maybe just 4 degrees, and increasing the lift by just a little. But curious to know if the lift should he increased equally or have one value higher than the other? The heads have been cnc ported and fitted with larger valves than the oem.

[@Ox78]

I have a 1970 WT block with #12 heads. I also have a 78 TA bock with 6X heads that I’m gonna port. The WT has an 067 Cam factory. Could you tell me anything about the performance? And also what program do you use to run tests

[@Ox78]

My motor has edelbrock torker intake, 750 Holley carb, and long tube hooker headers

[@rogerharrelljr1935]

By the way my 6x-4’s has casting flash in both intake runners and I mean they’re EXTREMELY bad!! From the floor there is certain flashes that’s almost a qtr inch tall!!

[@mikespeck8642]

Question: At what point do you know you have gained the most volume without killing velocity, during a porting job ?

[@johnbecay6887]

love your content. any idea where i can find a porter to work on some iron pontiac heads? thanks

[@LSxHunter]

Where are you located?

[@johnbecay6887]

@@LSxHunter thanks for your rapid response.. i'm in aurora co. where are you at?

[@LSxHunter]

I’m in Southern Mi - your best bet in that area might be Bruce Fulper

[@johnbecay6887]

@@LSxHunter thank you I''ve heard good things about david Vizard thopogh he lives on the east coast, i think..

[@richardhooper7323]

What computer web sight are you using?

[@donschofield4849]

$200 reward for location and photos of a rare set of Pontiac heads. Diamonds cast under the valve cover along the inside making a chain like pattern, in a gasket like pattern. Chambers swirl @spooned Ying, Yang. I/E, Butler said "they are not all that you would think and ; they're not real hi performance, And he has only seen one set of those heads".

[@stukksmith122]

Would that be a heart chamber like a vortec?

[@timsharpe3498]

Before you pick up a grinder you need to learn exactly which areas need work and the areas to avoid grinding. Pontiac heads will benefit mostly from better exhaust flow. For example, the Ram Air 2 heads have basic everyday Pontiac intake ports mated with much better exhaust ports and they can blow the doors off of everything except a 425 HP HEMI. Exhaust port grinding is almost always concentrated around the roof of the ports. The floor of the exhaust ports isn't very important. The intake side is an entirely different matter. Off idle and midrange performance is improved by working the floor around the short turn and high RPM power is increased by concentrating around the port roof, valve guides and long turn radius.

[@hotrod6919]

Can't really depend on looking at the cfm numbers everyone understands flow vs velosity but most overlook the overall port shape. round vs rectangular ports with exact same size will have completely different flow numbers round= high Velosity good low to mid and rectangular= high flow and great top end. Same with valve size 2.11 intake will always outflow and more power then say a 1.90 but at what rpm and overall gain vs The smaller valve flowing way more airwhile earlier while opening and at lower lift. But a good camshaft can usually fix or help with shitty head flow or efi and a china choo choo

[@lancereyesromero7811]

Are bigger cams really required when the heads are ported?

[@doomman700]

Depends on your rpm goals. Cam dictates what rpm the engine runs efficiently

[@lancereyesromero7811]

@@doomman700 almost 7k would be good. Turbo 5 cylinder. Weekend car. I don't want to lose driveability specially around traffic

[@LoganDidItYT]

I have a 74 400, 2801, 4x-1h heads, and dual plane Pontiac intake with a Quadrajet. I have ported the heads, but it’s not too extreme. Any ideas for improvements for more mid range? It’s a 4-speed car with 4.10 gears. I’m going to eventually swap to a 5-speed and probably 3.73 gears, but I’m curious about the engine for now.

[@LSxHunter]

A major factor is likely the cam - that being said the big thing right now is you're probably around 7.8:1 compression ratio with the 110cc chambers. Bumping that down to a set of 6X-4s knocks out 15cc from the chamber. It's not abnormal to see a 10% gain from start to finish with just upping the compression a hair. If you've got the "dreaded" double-eyebrow -15cc pistons you could use smaller 72cc heads that other guys are scared of. If you've got flat-top pistons a set of milled 6X-4s will make you more than happy. Cams are always good though.

[@LoganDidItYT]

@@LSxHunter thanks! Yeah, I know compression is an “issue” with this setup. I have a set of #17 heads sitting around but, I need to CC them- I’m finding some conflicting info on those. The cam that’s in the motor is the 2801. I haven’t started the engine yet, as I’m waiting on rocker nuts. But, maybe next winter I’ll have a new set of heads ready.

[@LSxHunter]

@@LoganDidItYT If they're like the 17s I have on my 350 they're 72ish cc. Those would likely rock on there and pick up a ton of torque. The 2801 puts you in good shape - especially if you want to jump to 1.65 rockers down the road. Most of the early heads are hard to find info on.

[@LoganDidItYT]

@@LSxHunter thanks for the help, man. The #17 heads are from a 1970 Firebird with a 350. I keep seeing that they’re 72cc, but when I did a ghetto flow setup I came up with closer to 90. I need to do it again, though. I did have the plug in when I tested, if anyone wonders.

[@LSxHunter]

@@LoganDidItYT What’s the date code on them?