Hi Guys, Just thought I'd let everyone know that Bulldog Performance has a website up and running. http://bulldogperformance.net/buick.html It appears as though R&D $$ are being saved by having all the various makes of heads cast with the same 76cc combustion chamber!ou:
76cc is alot in a Buick engine ex. bolt them on a stock '73 you'll have a little over 7:1 compression EDIT: 8:1 If you already have a "hot" 9.5:1 430 (69cc) headed engine you'll also need new flat maybe even domed pistons to get the 10:1 alu heads beg for EDIT: OK a little overkill, sorry. But just swapping heads will only give you 9:1 compression. You need to get rid of at least 10cc in that chamber PS: If these 76cc indeed are "generic" then they are not optimised for the large Buick bore and there will be little to none quench effect PPS: Pricing seems to be in the same price range as TA heads (64cc), so why bother ou:
Couldn't one just machine the heads to get any combustion chamber size you'd want? Maybe Bulldog wanted to allow a broad range of combustion chamber sizes for different engine configurations. Seems to me a 76cc size would be pretty good in a blower or turbo application to keep the static compression low. Before slamming them as junk, maybe we should wait to see what the fininshed product will have. 300 cfm out of the box sounds pretty damn good to me. Just my oppinion.
What Mike said, exactly! Also, the bit about needing a flat top or domed piston to get 10:1 is not correct at all. With a dished 22cc piston, .040" gasket, and the 76cc chambers you would be at 9.79:1 with 0 deck height, which I believe is what most people are currently going to on advice from Jim Weise and others. A flat top would put you at around 11.2:1 (0 decked). A 25cc dished piston at 0 deck would put you right at a very streetable 9.55:1. Having the bigger chambers, in my opinion, gives you more options (it's easy to cut the heads down to what you want). I think what is more important is the shape of the chambers, which there is no picture of on the bulldog site.
Mike and Steve, I'd say you hit the nail on the head!!:TU: The Bulldogs should be able to be 'adjusted' to work with whatever your goals are. Every aftermarket head I've ever worked on, whether iron or alum., could be machined down to reduce the comb. chamber cc's by quite a bit. The Cadillac guys are just now, starting to get a handle on what can be achieved with these heads. Richard Potter has already gotten the intake into the 375cfm range....with more to go. He expects to hit the low 400's. It's more than a bit premature to condemn heads that nobody has had a chance to work on yet.:Smarty: Below is a picture of the Bulldog chamber for the Olds 455. This is from Dick Miller Racing.
The Cadillac heads from Bulldog allow you to either use the stock style rocker shaft system...or an individual stud/guideplate style system. That's a pretty nice option - should save some money by using readily available and cheaper Chevy or Ford type roller rockers. Here is a pic of the top of the head.
Hi Guys, Just wanted to post this disclaimer... I definately intended in no way to slam Bulldog by my remark concerning the 76cc chambers. :Smarty: I can definately see where they can "come into there own" for a supercharger/turbo app. when compression needs to be low for boost reasons.:TU: But...think about how much bigger those chambers can become once you do chamber work and then how much will have to be milled to bring them "back down" for high compression non-boosted apps! Something to think about there...
Sorry, I have now calculated the compression ratios and edited my post. But it doesn't change the result much. You cannot IMO buy these heads as an "upgrade" to your running engine, you need to mill at least .05 off these heads to make them useable (and they need some chamber work too, look like s***. Add another .01 milling) Building a new engine is another matter, then you can just buy suitable pistons I must say if Bulldog decides to add the screw-in stud option, they have a winner
Here is the consideration and concern with a chamber maybe a little bigger than we want it to be, as cast. Aluminum headed street motors want about 10.5 to 1 compression. Your going to have to mill quite a bit off the head surface, and of course run a zero deck block, with 20- 24 cc dished pistons. At that point, you then need to tailor the head chamber to the correct CC to attain the compression your after, with the gasket your using. I highly recommend composition type gaskets with aluminum heads, and my personal preference based on experience is the TA Orange gasket, but I do believe if it was required to loose a little compression, the Corteco .060 thick white ones. I have used those with good success on an iron head motor, that we could not get a big enough combustion chamber in, due to them having been milled excessively in a "past life". We know that we are sacrificing a little power with the increased quench distance, but it's a lesser of two evils thing.. too much compression, and the requirement to mix race fuel that can come with it. Generally not a good thing on a street motor. Now, back to the milling.. There is no free lunch here... Typically milling .040 off the block to attain a zero deck height, already makes us have to mill the intake sides to re-fit the manifold.. and that in and of itself can be a little tricky. I like to use a .060 thick composition gasket on an aluminum intake/head combo, for the best seal. When fit correctly, there is no need for any type of gasket sealer, but your fits have to be right on the nuts. Intake side of the heads has to be milled at the precise angle, and sometimes we have to touch up an intake surface just a little, to correct a factory issue. This is most commonly a problem with the dual plane intakes, but I have had single planes that were "tweaked" a little. The worst one I recall was a wildcat.. it would actually "rock" on the motor. We milled the sides slightly, and then in conjunction with the .060 intake gasket, we attained a good seal with it. And we are not done yet, in fitting the intake.. my personal preference for an intake end seal is the factory style rubber seal, and in the typical TA Perf STG 1 Alum motor, we have to cut the block .040, cut the intake flanges of the heads about 1.4 x the head cut (there is no perfect rule on that, as every intake is a little different, and each engine needs to be fit as an individual. Typically, in that TA STG 1 Alum head motor, we have to mill around .050 off the end rails of the block, to re-establish the proper .0200-.210 distance between the bottom of the intake, and the front and rear rail of the block. So... all of the above is using TA heads... and that whole process of individual fitting, cutting, re-fitting and "dialing it in" costs around $425.00.. Machine time, and fitting time. And thats' with cutting just .004 off the TA head surface. Once we have established the correct fit, then another mockup has to occur, to establish the correct pushrod length, with the now re-fit and zero deck engine. Now, if someone told me that I had to cut .040-.060 off the head, that complicates things even more. I have in fact done that in an 11.5 to 1 compression STG 1 Alum motor, with a 20 cc dished piston. To get that compression, flat tops could not be used, because we would get it up too high, in the 12.5 to 1 range. Now... 76 cc heads with .040 gaskets, 24 cc pistons (speed pro's) and a zero deck block is going to get you 9.5 compression. that's a full point off where you want to be. TA's head typically comes in at 67-68 CC, with just a .004 cleanup cut. That will yield 10.4 or so, with the less expensive Speed pro pistons, and will give you the most bang for the buck, in a street motor. You certainly will be able to build that motor with Bulldog heads, but realize that you will have to use a more expensive piston with a smaller dish, and will have to do more cutting and fitting to make it all work. That amounts to more money, no way around that. So if the heads are the same price, then I guess I would not see the point of using them for that particular application. Now, there certainly will be applications that are advantageous to have that bigger chamber, looking at turbo and Supercharged stuff. And I also agree that any conclusion about a product that is not yet on the market is pre-mature. JW
well machining a head .010 is going to be a small price in the grand scheme of machine work when building up a set of heads. If the Bulldog and TA heads cost the same and if the head is flowing 300 cfm out of the box, and you can use small block Chevy type rockers, the savings over a set of TA heads will be HUGE even with the chamber work (if needed) and milling.
You may be correct here Kerry, in a your assummtion that he's using a chamber from another head. I would suspect that to be the case, but since I have not talked to him, I cannot say for sure. I do have it on good authority that the head has mopar intake ports in it. That my be neither good nor bad, just how it is being done. JW
Just a note to keep everyone on the same page here. In an iron Buick head, .005 cut equals 1 CC TA aluminum heads need more like .006 cut to get 1cc in volume reduction. Not sure what this new one will need, but if your looking to optimize the compression with the widely used current pistons/gaskets and specs, then your going to need a bunch more than .010 cut off the head. The issue is finances.. costs more to cut a bunch off. And I have heard no mention of indiviual stud type rockers being available. Looking at the casting, you will see that our Buick heads will not easily accept this modification. Individual pairs are available, but that rocker setup from T&D is over $1000 for the parts. We have a set in the shop right now. I'm not at all against this new head.. don't get me wrong here. But I think this chamber sizing is a mistake, for the "average" guy who wants to just bolt a set on. That ain't gonna happen. That is exactly why Mike's heads have the size chamber in them that they do, and are dimensionally very close to the iron heads. Ease of changeover. JW
Sorry about the reference to SBC rockers, I was looking at the pictures of the Caddy heads which I see offers this rocker option and has been rumored to be available on the new Buick heads. Until we see a set or get more info it is only a rumor. I still don't see how machining even .040 off the deck is going to substantially increase costs if no other port or CC work is needed. I just looked at the site and it states the combustion chambers are CNC machined, so they can't be even close to looking like, or needing the work, that the Olds chamber did in the picture that Scott posted. I'm currently running 73 Stage 1 heads (originally 74cc I think) that had .040 taken off to decrease the cumbustion chamber size and the only mod I had to do is run adjustable push rods. I can't see there being much difference in what I had done with my iron heads to what one would do to the Bulldog heads. Is my thinking wrong here?
Mike, I think we need to let the product come to market in it's finished form, before you can really get into these types of discussions. At this point it's all speculation. JW
Yeah---Good point Jim---you ought to see how long they've been claiming the Olds heads were going to be available--still can't buy a set.
