History of Chevy's NASCAR Engines: Small Block Evolution Details Up Close With a Legend (SB2 & R07)

if you're familiar with any kind of racing engines at all you've probably heard of an sb2 especially if you're in a NASCAR you might be wondering obviously it's called stock car racing and the cars are not stuck the engines are just as not stock but at one time they were and you probably wondered how did it get from being a stock car stock type engine to these all-out clean sheet race engines we have today you're gonna get to see all the details up close with the real parts from a guy who has lived the entire era from the stock block stock head era all the way up until the modern ro7 it doesn't get you familiarize before we get into this generation one is the stock block Iron Head generation two we'll call that aluminum heads like the Pontiac casting that you've heard about maybe with that generation 2 will also include the 18 degree as cast heads since the Pontiac heads were basically turned into that and then we'll call Generation 3 the sb2 that's where the biggest difference comes and then you have the ro7 which is the evolution of the sb2 and that is the current engine it's also worth no noting that from this entire era all of the General Motors teams were using the corporate small block Chevy engine we're here with Keith dorton an Automotive Specialist Racing Engines I couldn't think of anybody more qualified to tell us why would you be so qualified it is why did I call you well I guess cause we've been doing it all our life started the business in 1965. of course there were Big Blocks back then but as we progressed you know they changed the roof to small block we had to use a basically a stock block like a truck block we would put a better main cap on it but mostly General Motors bars we actually used a stock General Motors crankshaft to start with but the engines were making less of 600 horsepower at that time because these early blocks were bad to crack down in the wedding and so forth this this pept tile all that together early Billet caps that were made to you know big difference yeah it's big differences you know instead of cast iron it's a Billet for one thing and it ties into the block which is actually straightens the block as well as the cabinet set the factory four bolt caps were not splayed like that were they no no they weren't they were straight down see what the drill their own holes for that too yep so if you started with a factory four bolt block did this blade thread holes interfere with the Fret holes that were already in there it tied right into the meaty part of the blocks did anybody try to experiment with taking a factory two bolt block and doing that like theorizing that it would have more meat in here from not having that thread cut in it they did yeah yeah did that work it did Junior Johnson was the first one that I know of that did this he wanted to run a larger cylinder bore and a shorter stroke I'm not sure exactly what his reasoning was but today in England priority today we found that a larger cylinder bore would let the head breathe better wasn't as restrictive on the routing the bowels and so forth shorter stroke that changed the compressed knife for the Pistons a whole different deal the way to do that at the end the only block you could get was a 400 cubic inch small block they were all two bolt veins so what we did for junior then Billet caps made for the 350 main size and we made a spacer to go on the Block 400 Main which was a little over 200 000 bigger but uh put the spacer in the block cap on it that was the correct size for a 350 crank and line board it like say about 400s for two bolt so we've been splayed caps on them like that that worked out for good quickly when they come out with the bow tie block later on that quickly evolved that's what everybody did used a bigger bowl shorter stroke is that the same Arizona was running the 180 degree headers and stuff on his cars yeah you were building these engines back then we didn't build these engines we did this block work and cylinder head work were the cylinder heads you were using like a factory like a Corvette head or do you remember what it was from the very first ones were Factory type he had quickly evolved in what they referred to as the bow tie cast iron head required an extension from out of work so it was all done by hand the heads were very fragile it was a given they were going to crack in a 500 mile race we actually found some ceramic sealer that we sealed these heads with before we put them on the engine and then race day one of the things the last things the guys had done before the race started they'd pour another bottle of this ceramic sealer and let it circulate because more times than not the head would crack during the race and this sealer would let them finish the race sometimes they could be repaired sometimes not I don't remember how many years we had to run those things but I remember we eat a lot of cast iron dust I bet you were relieved when that changed oh yeah it's just a Pontiac when Pontiac was still involved in racing they're the ones that actually went with where Chevrolet did too they had a bow tie aluminum head but everybody ended up earning the Pontiac head that was made by brodix for Pontiac and much more reliable head a lot easier to work with than the performance was better too but the longevity was outstanding compared to those gas tanks it's heavy too but you can see the difference in the intake runners intake Runners raised up which gives it a straighter shot to the valve in the combustion chamber now what would the power difference from this era to this error be we when we first started with these things and these things evolved over a number of years by changing the Val ain't going by Milling the deck on an angle which in turn changed the valve angle which in turn gave the straighter shot to the cylinder in the valve before any of those modifications it was probably in the 30 horsepower range but it evolved into hmm The Next Step I don't have one of those to show you was the 18 degree head that Chevrolet came out with and the biggest difference to me it was in the bowel angle and a little different intake runner just looking at them side by side you're not going to be able to tell the difference of course you took one of these and welded it up and milled it to be 18 degrees or something and it was essentially like they were making what you guys were doing to this already that happened yes yeah so that's when you started getting in the 100 horsepower gain over the original cast iron heads the next thing that I can show you is the SP2 you get more of a direct shot intake Runners raised up you see how much prepared from here to the bottom from here gives you a straighter shot to the valves a bigger Runner staggered valves gives it more airflow on both the intake and exhaust wasn't it 1998 that the first time the sb2 was run I think so right real closer 97 98 there's basically a whole different engine the the blocks were different same block height but the lifter for staggered something that is not apparent by looking at this stuff on a bench is that the traditional small block Chevy the intake manifold has a water passage in it that's where the thermostat is and the distributor goes through it also the sb2 got rid of both of those things the sb2 had a separate Valley plate that had the water passage in it with the distributor hole and the intake manifold was totally separate from those things so you could take the intake manifold off without having to screw with your timing or have coolant everywhere much better design for working on a race car but that was a really major change that's when the engines went from 700 or under to 800. quite a bit of difference and all around on this head it's just you can see even on like exhaust side the difference how the runners are hot taller yeah it is looking at it at an angle right how much of the valve that there was of out there how much of the hole you can see out here versus there it's like looking you can see straight through it right but not here yeah I think I did see on here because this is the Hendrick head that it had this uh port on the water jacket inside here foreign [Music] gasket happier between these cylinders right yeah yeah this thing uh these are Siamese and the block is also between these cylinders uh which is a good time to point out that that from this to the RS7 this went from a full 400 bore spacing to a four or five hundred which gave more room in between here as well as getting rid of those two exhaust valves so that helped a lot but this these are drilled in between uh and then this is actually pulling water out here to keep it flowing between the two exhaust valves there's the the 184 bow tie block on 18 degree heads it's at the same block that the sb2 started on or did they come with the roller like one of the roller cams in the offset lifters and everything become the standard if you could steal both the SP2 head on a conventional like a 184 bowtie block so but it takes a special camp so quickly evolved into SP2 having its own block staggered lifters that more fits the cylinder head configuration because you could take an sb2 head and bolt it onto a standard small block Chevy block if you wanted to use a special camshaft and lifters that means you could take a NASCAR cup series head from early 2007 and bolt it onto the block from a Chevy K 1500 pickup truck with a 350 for that means the old small block Chevy architecture lasted longer in NASCAR than it did on the on the street because by then the LS engine had already been around for almost 10 years so you know maybe these engines were actually more stock car than you thought they were for longer than you did think they were well maybe you didn't I don't know is this news to you like speak up in the comments is that surprising but you if you want to look at bother them too this is is this like the evolved yeah SP2 block because it's got the um these on here I've heard stories about these or can you explain what this does well this brings the water if you can see the water normally comes into the front of the block on a small block Chevy but you're again with the Siamese Sports hottest Parts in the center so bringing the water into the center of the block instead of the front does that help with overheating it did obvious visual differences going on here this looks like a middle ground between a standard small block and r07 block right yeah [Music] yeah you can see the staggered lifter boards and the the original 184 bowtie blocks did not have this scavenge Port built into them did they they did it they did some regular Chevrolet does not have that in fact we uh we would drill you know and tap this ourselves did you have to rebuild those after every race we did in that era Daytona when you're down there for 10 or days or more and all the practice qualifying in the 125s pretty common practice back then though the best engine you run the 125 to get qualified and then pull it out bring it up here and turn it around for the 500. the year we want one to the 590 I guess it was that engine ran the whole deal but we were afraid to run 500 miles after running probably 200 or better so they pulled it out brought it up here that night Jeff and I worked straight through turned it around they got back to them on Saturday I guess that was the Derek hope in that year yeah what exactly would you have to do would you just refresh things or did things break already we uh this is only completely magnafluxed everything check the valves put new Springs in it fresh Rings most time we didn't have to change the engine bearings but mainly just inspect everything look for heat in the Pistons the next step over to the SP2 was the r07 which was again clean sheet of paper I'll show you the difference in the blocks as we go along here okay but as you can see from the head bolt pattern and everything's different similar but that in some ways I like the look at them from intake side Port spacing and all is very similar between the r07 and the SP2 but there's a lot of a lot of difference with the evolution of this thing the drivers really liked them because to start with they didn't make quite as much horsepower on the top end but they drove better they the torque curve was flatter then it'd accelerate better especially on some of the short tracks But as time went on in the development of this thing you know this one got over 900 horsepower yeah that doesn't look anything like what comes in a no production vehicle and if you look at this block and you look at a Toyota or Ford very sampler well what were the biggest reliability issues with the sb2 that the r07 fixed or was there really anything not really was there really even any need to do this if like was it needed or is it just done because it could be I mean this is just me speaking but uh no I don't I don't think it needed to be done I mean you know we could make the horsepower and Rob robility there but the big the big game here if we had an sv2 with the four or five hundred bore spacing which we've had Dart and some others do that some of other types of racing you know this as you can tell is specifically made for a squad of development for instance the the cooling system you know you've got this water jacket here and the way it flows and you can see how high the water jacket is see there's no culotte down here in the bottom part of the cylinder hmm then that's the weight yeah that's interesting that there's all the passages in here are kind of like externally visible and there's not just like a wall right one big difference that you can see between you know the stock block and like this evolution of the small block is look at the size of the cam tunnel and the size of the main bearing it's like they changed diameters right they switched each other right yeah this was speaking of back in that era it was just opposite you know now we're running a 60 millimeter roller cam and a two inch main bearing so now that wasn't possible back in the early days because of process and materials on the crankshaft we went to when we first started using roller bearings roller cam bearings we went to a 50 millimeter oh yeah which was a common bearing it was not a bearing made specifically for automotive use and then we just stepped what was available adapted the smaller cams of course they were cast cast iron before and we had trouble with them breaking and even with the steel cams small diameter at Power PMS we had trouble from twisting you know the timing would vary from front of the engine to the back of the engine so that's the thing of the past now that's interesting that in the early days the crank Journal had to be bigger to keep it alive and now it's the cam yeah it's like maybe some day material will evolve to the point where the cam can be smaller again it won't twist itself yeah it's just 180 from what it used to be 20 years ago they said you know it's craziest work well it wouldn't work 20 years ago what were some of the shortcomings of the sb2 head that were revised for the ro7 head it's like the most obvious one is the these Center ports here yeah they're not right next to each other anymore yeah yeah that was always been a kind of a heating issue you know on the small block with the two exhaust ports being right together so that did help that the the tendency the sb2 and we still use a lot of these but primarily we used sb2 for our land speed engines land speed racing racing on salt lats you're running on a real narrow tire and a relatively slick surface and you can't use a lot of low end power the sb2 was more of a upper end power range they didn't know when it quit they still don't you know I mean if you've got valve train it'll stand at 10 000 RPMs you know they're still making good horsepower didn't the C3 come out and it was stomping the brutic head and then the SP2 came out to fight for it on the C3 pretty much yeah yeah because that that we were doing a lot of the C3 Ford heads at that time also so you were building all the manufacturers for uh yeah NASCAR teams back then that's interesting yeah that could never happen now yeah no no we never got involved with Toyota if you guys were building everybody's engine could you kind of help people out in a way kind of like oh this C3 is better we could do this this and that to make like the Prototype better you had to be very careful about how you approached that in that uh since we were doing basically the three manufacturers you know I didn't I didn't want to and I didn't have favors you didn't want to tell the Chevrolet guy that the Fords got 30 more horsepower yeah or the Mopar guy you know yeah yeah whatever yeah I didn't know if they were aware of that or if like any of that was ever discussed how'd you walk that line yeah that was that was a fine line you had to walk quite honestly that all of them had different characteristics in that time you know there's a lot of similarities now between the Toyota the Chevrolet and the Ford I mean you know the regular mechanics and might not even be able to tell the difference you know just like the chorus in that era the engines were anybody could walk up and see the difference between Ford Chrysler Chevrolet the characteristics were different but we had to be uh a little uh politically correct I guess you'd say since we were doing work for all of them uh and then you had to contend with the drivers too you know Jack's got more horsepower than I got he can accelerate better or on and on and on you know he's beat me down straight away that happens even today with the same brand and we had it back in that era where two Chevrolets running together when I was running better Nether and in reality they could have swapped engines and they'd still been the same way maybe it's something to do with the car maybe some do with the driver I guess the big biggest single Improvement in evolution was between here and the SBT you know it was more gradual from then and now that the increases in power from very small increments a lot of people would know your brother as the the Hendrick engine guy yes sir and you were doing your own thing over here but what point did you go different directions and did you ever talk to each other about this stuff when you were not on the same roof anymore hey uh once he started with me when he was you know just able to sweep the floor just young enough and he was 10 years younger than I am he was he picked up really quick and worked for me for years and we did uh a lot that was in that era where we're doing a lot of those things a lot of the NASCAR stuff in fact uh he uh had a hand in quite a bit of it as time went on when he got out of school he wanted to see the world so you were drag racing Martin who we would do we did a lot of work for them and some of the other guys and he got to travel and then when he kind of got to settle down you know Harry Hyde offered a job which you know I'm I'm proud to be a part of what he did and I'm even more proud of what he did on his own starting and then devolving into working with Britt so he had a hand in the development of the SBT as far as sharing we the sharing information after he went to work for Rick and we were doing our own thing when we we would have socially with the family we didn't talk about this we I didn't want to infringe on him he didn't want to infringe on me a common question because we did a video similar to this about the Ford Evolution and people are like well what was the specific horsepower of the C3 versus the D3 and the fr-9 like there's not really a clear answer to that because everybody's was different and you had incremental gains in each one right over time it was like it was the platform change it wasn't like a power light switch changed that's exactly right you know you know the only way to do that is with uh Power adders snipers boost one thing we haven't talked…