1. toneitdown2 on July 8, 2020 at 7:20 pm

    You said you got the heads used with worn out guides. Is that why you had to replace everything is because the heads needed rebuilt ? And what CC were these heads advertised to have ? They start at 305 up to 360CC ?

  2. dragginwagon406 on July 8, 2020 at 7:22 pm

    So much to learn from your videos, even in the photos at the end.

  3. Rat Gas Garage on July 8, 2020 at 7:23 pm

    Hey buddy love your channel! I have a question for you, have you ever come across a leak near the back side of the oil pan next to the flywheel only when revved up, on bbc 454, idling is fine no leaks, I’ve redone the pan gasket thinking that was it, but still happened, I also added evac system it didn’t help

  4. Mccleje11 on July 8, 2020 at 7:25 pm

    Why not go with 110cc chamber? I am trying to learn the offset of velocity vs size.

  5. Jason Fikes on July 8, 2020 at 7:27 pm

    Thanks for sharing that. Was considering those until seeing this video.

  6. supercharged6771 on July 8, 2020 at 7:30 pm

    I hope for all the up and comers reading and watching this. You get what you pay for and when you get there do LOTS of research in the area your working

  7. manitoublack on July 8, 2020 at 7:31 pm

    You’re alive!!

  8. Stuart Cookie on July 8, 2020 at 7:33 pm

    Reliability is NOT an issue with these heads…purchased a set approx 6 years ago to hold the door open to my shop and have never had an issue as they have performed flawlessly!!

  9. kmcwhq on July 8, 2020 at 7:34 pm

    How far ‘off’ is the factory main bearing bores? Was GM that incompetent that most all speed shop engines need to be Line Honed to make them more accurate?

  10. Bill Wall on July 8, 2020 at 7:34 pm

    You know the BBC well and I learn alot from you on making reliable horsepower, your attention to the details and overall knowledge of the Gen 1 engines is amazing! I agree with others that Procomp heads are not a good investment

  11. Matthew S on July 8, 2020 at 7:35 pm


    What’s your go to head for the 467 BBC setup?

  12. Ozzy on July 8, 2020 at 7:35 pm

    I had that exact same set of heads and sold them before trying them because after I researched from other people they said the same thing.They cost too much money for the little gain you get. I stayed with my 781`s.

  13. Bobby Bowers on July 8, 2020 at 7:36 pm

    I agree this setup should have made better hp and tq

  14. Jos Buijk on July 8, 2020 at 7:37 pm

    He’s right , I have the same heads. Purchased from Skipwhite. They did put in really good valves,seats ,guides and retainers.I did put in comp cam springs and my Corvette runs like hell. So ,resumed : The casting is perfect but the original valves ,etc are bull shit. So buy bare heads and put in quality stuff.

  15. The1969ssx66 on July 8, 2020 at 7:38 pm

    I’ve used three sets of pro comps, Automatically new valves and set up with comp matching springs to the cams used. only polished intake and ran good numbers with three different cam combos.

  16. David Reed on July 8, 2020 at 7:38 pm

    I even cut a bevel at the top of the block with iron heads. Imagine what the air is hitting coming into the cylinder from those heads. I would want to weld them up and take a cutter to them

  17. john smith on July 8, 2020 at 7:38 pm

    great video……the guy who owns the motor it probably been cheap to buy good quallity heads to begin with…..?..i know machine work is not cheap….

  18. Struinzu Vaffencullo on July 8, 2020 at 7:38 pm

    Says he doesn’t like using chinese heads, then rattles off about 6 other offshore products…

  19. Dave vonAnderseck on July 8, 2020 at 7:43 pm

    I have a question. I rebuilt an 8.1 496. Haven’t started it yet I’m waiting for intake carb push rods and rockets. Bored 30 over. ARP rod bolts. New flat top pistons.
    Heads cleaned a little exhaust port work. Comp cams springs.

    My question is when it came to the head gasket the only choice I had was felpro. I noticed a LOT of gap between cylinder walls. Is this ok?

    Also I noticed had no alignment pins for the heads.

    So I cleaned the threads. Got new head bolts. Used a little lube on the shoulder and torque to 60. Also I sprayed copper gasket.

    Honestly I have my fingers crossed and hope it’s dependable. When I torqued my bolts some would torque earlier.

    Any advice what’s your take on this. Should I buy a better gasket is it worth it.

  20. Bright Star Last Name on July 8, 2020 at 7:44 pm

    7:52 That’s dated "Nov 2, 2005 at 20:55:24"
    Could I please get one of your time machines? I want to buy some stock.

  21. Pop's Garage Mayhem on July 8, 2020 at 7:46 pm

    Must be a happy dyno, with that small cam…

  22. mike f on July 8, 2020 at 7:47 pm

    I enjoy these engine building videos and I have learned a lot of details that make things cook.
    I am considering doing business with this outfit, does anybody know how to reach them?

  23. TDA DIY on July 8, 2020 at 7:49 pm

    Truck head question. I have a 366T with 473328 heads. I had an engine vibration. I took heads off and found exhaust valves were mismatched. 3 valves in one head were flat bottom and 1 was concave. The other head had 3 concave and 1 flat bottom exhaust valve. Would the valve shape being different in one cylinder be enough to change compression in that cylinder to cause an engine vibration? Having 1 cylinders valve being different than the other 3? Thanks. I’m wanting to use the 366 truck heads on a 68 396 short block (bored .030). I realize I may have to clearance cut the chamber to clear the #1433 raised dome (9.6 comp). piston. It’s for a 58 belair street car. I want small valves and oval ports for good torque. I wont be revving it past 5k if ever.

  24. Spiro Jannings on July 8, 2020 at 7:50 pm

    Good job Mark! Also, while Redline Racing Cams website is being revised I may be reached directly at 408-292-0646 PST

  25. brgable1976 on July 8, 2020 at 7:50 pm

    would love to see you do a side by side with AFR 300 heads on a 496 compared to a set of GM ovals that you’ve worked over.

  26. Robert king on July 8, 2020 at 7:52 pm

    Hey Mark, don’t you have the same issue with AFR heads as far as head gasket?
    I know when I build my 496ci
    4.450 was the size of gasket I had to use, other wise the gasket hung over the combustion chamber.
    I bought 4.375 and they wouldn’t work, so the closest I could get was 4.450 , on a set of magnum 290cc oval port 112cc chambers
    I used a .030 MLS cometic gasket with the piston .007 in the hole.
    On a dart big M block

  27. Michael King on July 8, 2020 at 7:53 pm

    The numbers put down on Hot Rod Garage were rather sad as well using these heads. I think they are a fantastic head if you plan to buy them to have them ported. From what I understand they make an impressive cylinder head once worked over. Out of the box however they are barely better than stockers.

  28. g cis on July 8, 2020 at 7:53 pm

    This guy is really hard to listen to

  29. supercharged6771 on July 8, 2020 at 7:57 pm

    Talking about heads without you having a hat on is distracting

  30. Monte Maguire on July 8, 2020 at 7:59 pm

    I need one for mr 2012 Silerado 4×4.

  31. Salmo Dantas on July 8, 2020 at 8:00 pm

    Hi have you already made a strong engine with Vauxhall?

  32. Nelly Farnsworth on July 8, 2020 at 8:00 pm

    Thanks about the warning ⚠ about China heads.
    Stock chevy. L.S. will flow these numbers??

  33. Leo Hollie Jr. on July 8, 2020 at 8:01 pm

    Run dyno b4 and after mods are done to the heads. Let us see the gaines or losses.

  34. Drew Sharpe on July 8, 2020 at 8:02 pm

    I had a set of 049’s you ported,they were a work of art!!

    I think everyone realizes Speedmaster/Pro Comp heads need a good bit of work. What makes them so attractive on any big block is the saving of ones back😂 Its no joke to go removing an iron big block head in car.

  35. Nelly Farnsworth on July 8, 2020 at 8:05 pm

    Mark, What would you do???
    Big Block Chevy 427 Tall Deck, Industrial engine, that has stock FACTORY reverse gear drive, with four bolt mains & steel crankshaft.
    I learn alot from these videos about a solid reliable Big Blocks.
    Also like NO music 🎶.
    Just the facts.

  36. Joseph Wiseman on July 8, 2020 at 8:05 pm

    Let’s do 427 bbc next.

  37. mike f on July 8, 2020 at 8:06 pm

    In this build, he mentioned using a Scat 9000 crank. KB/Icon makes stroker pistons for 402 to 434 builds. His massaged 781 heads should wake up a 402/434 I figure. Need to talk to these guys, love the way they do the videos, laid back basic machine work. 620hp/647= 1.327 hp/ci.
    434 x 1.327 = 576hp, sounds like fun.

  38. John Ringel on July 8, 2020 at 8:08 pm

    Bottom line. Spend more money upfront for better quality heads. Save yourself some hassle, and be better off in the long run. Thanks for the video. There is good, and there is cheap, but there is no good, AND cheap.

  39. a a on July 8, 2020 at 8:09 pm

    ported factory heads, make my machinist happy?

  40. a a on July 8, 2020 at 8:09 pm

    i am a bbf guy but love hearing you talk about rarely found rats in everyday life. big blocks dont daily drive

  41. MSH68 on July 8, 2020 at 8:09 pm

    I wonder how the Edelbrock aluminum heads compare quality wise versus the Pro Comps? Better geometry and parts?

  42. dirtfan05 on July 8, 2020 at 8:11 pm

    I don’t care what brand head you buy, I don’t buy any of them complete, I load them with my own components so I know what I have when I’m done.

  43. hayden spence on July 8, 2020 at 8:11 pm

    Excellent video thank you bro

  44. Deleted on July 8, 2020 at 8:13 pm

    I think he’s trying to say , “buy bare heads” and assemble with quality parts. Also see the video on valve seat concentricity….👍

  45. Tom Hutchins on July 8, 2020 at 8:13 pm

    Believe it or not i actually agree with him on this one. I actually think he his understating the issues with pro comp heads. Seat heights and seats barely in the casting (falling out) is another issue. There is very little right about them.The heads are also very thin light weight. Pro comp has an other version with a 360c intake and oval exhaust ports that is a much better part. Much better quality. thicker casting. Seem to be a copy of the old pro action heads?
    He bashes a much better head like air flow or brodix but he is polite about pro comp?

  46. Nick W on July 8, 2020 at 8:14 pm

    And then spending the same amount as a set of AFR heads after all the machine work, they are ready to perform half as well..

  47. metal devil on July 8, 2020 at 8:16 pm

    Get a set of Brodix BB-2 plus heads bare and have them blueprinted with top shelf parts for your 427-496 rat.

  48. Carpathian on July 8, 2020 at 8:16 pm

    I have a stock 1972 454 in a Corvette original to the car. What heads would you recommend to liven it up some for a weekend racer and a cruise now end then?

  49. Rat Gas Garage on July 8, 2020 at 8:16 pm

    Btw, it only started leaking when I took it to the track and pushed it hard, I was also told it could be crank flex that would cause the rear main seal to leak under acceleration, your thoughts would be greatly appreciated thanks

  50. cheveefarmers on July 8, 2020 at 8:16 pm

    i did a video on a set of procomp rectangle ports heads after 10 years of use on a drag car. not trying to pimp out my vid but might be worth looking at?

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