How many cases are there of the same block being offered with completely different types of cylinder heads in the same car in the same model year? Examples that come to mind:
1) The Willys Aero with the flathead and the F-head sixes. I can’t speak to fitment of these engines in Jeeps, nor to the Willys flathead and F-head 134 CID fours.
2) The Peugeot 405S and 405DL were SOHC. The 405Mi16 was DOHC.
3) The Saturn S series: SL1/SW1/SC1 (SOHC), SL2/SW2/SC2 (DOHC).
I know Studebaker made their flathead 6 into an OHV in the late 50s or early 60s, but I don’t think they offered both versions in the same model year. But I’m no Studebaker expert.
What other examples are there?
The 2003-2004 Supercharged DOHC 4.6 SVT Cobra shares the cast iron Romeo block with the 2003-2004 Mustang GT 4.6 SOHC. All other instances with the modular engine the DOHCs used an aluminum block.
AMC, with the 195.6 six cylinder overhead valve, and flat head versions. They ran the flat head all the way to 1965, in the American.
The Lampredi-designed FIAT engine came with OHV (124 series) DOHC (132 series et seq) and SOHC (cannot remember the code).
Blocks weren’t identical, admittedly, but they were all the same famiglia..
Of course, I forgot those! From your mention of the 132, I assume you’re not in the USA. May I ask where you are?
Here in the USA, the 124 sedan got OHV. The 124 coupe and spyder got DOHC, as did the 131. I’m pretty sure we didn’t get a SOHC version of that engine–please tell us more.
I’m in England. Had a few 124s, both pushrod and TC.
The Special T 1600s had the 132 code, think the 1400 had a 125 code.
Later Lancias and FIATs a 134 code
So 124, 132, 134 were engine codes? I was thinking you were referring to actual model numbers–Fiat 124, Fiat 132, etc.
The 1971 XY Falcon and 1972-3 XA Falcon had both the standard 250 CI with the inlet manifold cast into the head and the 2V version with a bolt on aluminium manifold and two barrel carburettor.
Good call!
Toyota narrow valve angle 4A-FE vs. wide valve angle 4A-GE. Both DOHC/16 valve but the 4A-GE’s cylinder head was a higher performance Yamaha design. The latest 4A-GEs were 20 valves. Minor block differences.
If the “same block” can have a different displacement and internal components, I think the Cosworth Vega engine might qualify.
There were a few very minor differences between the Vega 2.0l and 2.3l blocks, but you’re essentially correct.
In 1987, you could get a Buick Regal with a 3.8 that had a 2-BBL and 110 hp and a turbo version of the same engine with a lot of the 3800 upgrades, sequential fuel injection and 225 hp.
Both had the same basic head design. The question asks about distinctly different/unique head design/architecture.
Toyota A-Series?
Gotta love “Flashing acceleration” =8-) .
-Nate
That term shows up in lots of old ads.
My point exactly .
I’ve been using it since the 1960’s my self after reading it in a 1930’s advert .
-Nate
And it often seems to be used with cars that are capable of making the speedometer climb at just better than a watching grass grow pace. I do seem to remember the Willys Aero being a fairly capable car, though. A friend has a 1955 Willys Bermuda with the Kaiser 226 and OD, but I’ve never gotten to hear it run. That should provide a little more dash yet.
On second thought, maybe it’s just an awkward way of describing someone who left their blinker on after merging onto the freeway.
BMW M30 SOHC (street) and M49/88 DOHC (competition) engines, slightly stretching the “same car, same model year” parameter.
The VW 1.8l in the 80s, came in SOHC 8V and DOHC 16V. Offered simultaneously in the Scirocco 2 and Golf/Jetta 2. There are some diffences in the blocks but are nearly identical and the internals swap. Same thing in the 90s with the 2.0l SOHC ABA and the (not offered in the US) DOHC ABF.
In the early 90s the GM 60 degree V6 was offered in rwd in the S10, Camaro, Firebird in pushrod form in a 2.8-3.4L displacements. The same basic block was used in fwd both pushrod and DOHC forms with only small modifications.
Triumph Dolomite (1850cc, SOHC, 8 valves) and Dolomite Sprint (2000cc, SOHC, 16 valves)
When I asked the question, I was thinking in terms of flathead vs. OHV, OHV vs. OHC, SOHC vs. DOHC, but you’re right—8V vs. 16V is certainly a legitimate difference.
To digress from the original question: IIRC, in the Dolomite Sprint a given cam lobe operated both intake and exhaust valves. This was true of the Willys “Tornado” OHC 6 also. Any other engines of which this was true?
And Leyland only knew why the TR7 got the 2000 with the 8-valve head! Shouldn’t a TR have gotten the best engine in the house?
Leyland marketing blunder #4,003,221. 🙂
There actually were plans to offer a TR7 Sprint with the 16-valve head, and they built 15 prototypes. In this era, general British Leyland dysfunction no doubt explained a lot.
The early Saab 99 had an 8-valve version of that engine–1709cc, then 1854cc. A Dolomite Sprint engine would make an interesting swap.
Interesting perhaps but there is a reason SAAB redesigned the Richardo engine to create the B-series. Retained the dummy shaft and internal water pump but lost the slanted head studs that made it almost impossible to remove a TR7 ( or Stag) cylinder head.
In 1964 Chrysler offered both 426 Wedge and Hemi engines. The Hemi block was modified to accommodate the Hemi heads, but was the same basic block.
Ford Lima 429, in ’69 and ’70 Ford offered the Boss 429 which had Hemi-style aluminum heads on a modified Lincoln 429 block.
Couldn’t get the Boss 429 in cars that offered the standard 429. It was a Mustang exclusive, and installed by a subcontractor that modified the engine bay.
Chrysler’s early hemis and poly V8s shared the same block.
1969-1970 Boss 302 and regular 302.
Paul, I believe that the Ford ‘Cologne’ 60 degree 4.0 liter V6 was offered first as an OHV engine in 1991-1993 (I think) Explorers with 160 net HP, then from 1994 through 2010 the same block but with SOHC 2-valve heads, giving a rated 210 SAE net HP. Not offered in the same years, but at least the same block with different cylinder heads.
I may be wrong about the years the 4.0 was offered with OHV heads – it may have started in 1989 or 1990 – or earlier?, and lasted a bit longer than 1993, probably in the Ford Ranger pickup.
That’s the best that my aging memory can do on this one.
But a great question, and some interesting and illuminating answers.
The OHC 4.0L V-6 was a mess. Ford used the same head on both sides, which of course required timing chains front and rear. Guess which timing chain set gave the most trouble? The block was substantially different between OHV and OHC versions, though there were some similarities.
Studebaker R3/4 V8s had heads that were unique, and required different manifolds and other parts compared to the regular V8 heads.
1991 Dodge Spirit: the Mopar Trans-4 engine was available with a DOHC head from Lotus in addition to the standard SOHC head made by Chrysler.
The various Lotus Cortinas and Ford Cortinas shared engine blocks while the Lotus had a twin-cam engine and the Ford had pushrods.
Not an expert, but I’ve read that the Ford SOHC big block from the sixties pretty much used the pushrod FE block with OHC heads.
The 427 SOHC was not a production engine. Built and delivered to racers only.
The 4th and 5 the generation Honda Civics had SOHC and DOHC version sof the D15 and D16 engines that appear to use the same block but different camshafts.
I think the late 80s-early 90s VW transverse 4 also used the same block in 8V and 16V form so a 1987 Golf GTI could have either head with the same block.
I can’t think of any other factory engines that were side valve and overhead valve on the same block although several side valve designs had aftermarket conversions.
The BMC ‘B-series’ engine.
In 1958 the MG A had the ‘B-series’ available with push-rod OHV or the Twin-Cam head and in 1966 you could have the Austin Cambridge/Morris Oxford cars with the ‘B series’ in petrol or diesel formats (same type of valve gear but very different head design).
A while back I read the autobiography of Gerald Palmer, who designed the Jowett Javelin and MG Magnette. He said he would have liked to see BMC offer the Twin-Cam engine in the Magnette. It would have been to the cooking Magnette as the Lotus Cortina was to the cooking Cortina.
Didn’t the Ford 240 and 300 straight sixes share the same block?
Yes, and essentially the same head. The question is about different types of cylinder heads, not the same basic design with small differences. There were numerous different cylinder head part numbers for all the American sixes and V8s, but essentially the same basic design or type. “Different type” means different architecture.
How about the Volkswagen 1300/1500/1600 “block” (engine case)? As far as I could tell with some quick searching, the engine case is essentially the same.
See my comment above.
Hillman 1724cc OHV came with either iron or alluminium cylinder heads different valve order camshafts and manifolds.
Always wondered about these. Was it just the metal or were there combustion chamber and/or porting differences?
There are some porting differences somewhere the alloy head engine pumps out more power very common in NZ all the Hunter sedans had them its essentially the Alpine/Rapier head
Audi 5 cylinder – SOHC 10 valve & DOHC 20 valve.
Ford 427 with OHV & SOHC
The 427 SOHC was not a production engine. Built and delivered to racers only.
Ah yes, true. Adding non-production engines (I’m looking at you Pontiac 421) would open the floodgates.
No need to give 421 the snake eye, is there?
Maybe the question should’ve been phrased as different cam arrangements?
No snake eye – Pontiac was pretty imaginative in working on breathing and cam solutions for the 421. Ford was similar in their tunnel port engines.
Agreed, but Paul seems to be disqualifying submissions that aren’t of radically different completely non-interchangeable design.
2009-2010 F150 – the XL’s had the 2-valve 4.6, XLT-trim and up started with the 3-valve 4.6.
IIRC, the reason base trucks had a downgraded 4.6 V8 instead of the traditional V6 was because the Essex plant where the 4.2 V6 was made was closed down, and the new Cyclone 3.7 was waiting for the 2011 engine refresh.
BMW (E28) 528e and 524td both had engines derived from the M20 engine. In the case of the diesel, it was designated M21. Whether these qualify as “the same”, I can’t say but they are very similar.
BTW, there is a potential “curbside classic” 524td very much alive in Eugene OR. Happy hunting!
Pretty sure the Chrysler 2.2 turbo in the early 90s had two heads. One for normal turbo 2s and then a different one for turbo 3 s ( spirit and daytona RT)
Also seem to recall the 340 V8 having two different head part numbers.
Re the 340: The question is about different types of cylinder heads, not the same basic design with small differences. There were numerous different cylinder head part numbers for all the American sixes and V8s, but essentially the same basic design or type. “Different type” means different architecture.
Chrysler also had the 2.2 with Maserati 16 valve head on the TC.
How about the 16V 2.2 in the Daytona ? Was it a Shelby design ?
The Honda D series came in the ’88-’91 Civic in both SOHC and DOHC versions. I’m not sure the DOHC version made it to the US, but both versions were available in other markets.
Honda engine families typically use many different head variations on the same block, so I’m sure there’s other examples as well.
The Jaguar AJ straight six had both SOHC and DOHC versions with slightly different displacements.
No one mentioned the Ford Yamaha V6 from Taurus SHO. Basically a Vulcan block with Yamaha heads.
It’s really not, it’s derived off the Vulcan, yes, but it’s highly revised for the DOHC heads and they don’t interchange
Pretty sure the W201 Mercedes 190E 2.3-16 used the same block as the regular SOHC 4-cylinder engine.
How about Ford’s 4.0, available as both pushrod and OHC in the same model year Explorer, etc.?
A “conversion” to the extent that the in-block camshaft location was used to house an intermediate shaft which drove the overhead cams.
Maybe I missed the mention, but fairly positive the original Neon belongs on this list, having been offered in both SOHC and DOHC configurations.
Come to think of it, so does the late-80s VW 1.8L (as seen in the GTI) for the same reasons.
Yeah I agree neon would meet the criteria, So far seems much more common on 4cyl then any other engine type.
3.1 ohv and 3.4 dohc v6 in the early 90s GM W bodies. Possibly an honorable mention to the LT1 and LT5 motors, though if memory serves the blocks were different.
The Australian XA Falcon GT qualifies. The 4 speed manual had the large port 351 4V heads and the auto had the small port heads 351 2V heads but used a locally designed four barrel inlet manifold.
The Nash 40 series flathead six developed in 1941 was updated with an OHV head in 1956 – to match the larger Ambassador OHV six. As was mentioned above, the flathead was still kept in production in the Rambler until 1965.
I and a few others who mentioned the SOHC 427 Ford were rightly called out, as it wasn’t a production engine. But how about the Ford Kent in-line four? Basically the same engine with two different OHV heads, the original and later a cross flow head, and then DOHC in the Élan, Europa, Lotus Cortina and RWD Escort, the last of which is definitely a case where the same car was sold concurrently with both pushrod cross flow and DOHC engines.
Ford Cortina 1500cc OHV Lotus put their own twincam head on it in the Lotus Cortina
Isuzu G180 and G200, used on the 117 Coupé, were available with one or two overhead cams throughout the 70s. I’m sure Nissan did this too but cannot remember which engine or model…
Toyota loved to offer SOHC and DOHC versions simultaneously but from 1974-77 Toyota licensed Honda’s three valve CVCC design, which was branded TTC-V, and produced the 18R (SOHC), 18R-G (DOHC) and 19R (TTC-V).
Porsche 944S and 944 in 1987 and 1988. Same 2.5L block, but with a 16V DOHC head in the S and the 8V SOHC head in the base car.
Nissan went for a triple circa 1991: single-cam heads on the VG30E, close-quarters DOHC heads for the VE30DE, and regular-size DOHC heads on the VG30DE and VG30DET.
Paul, would you consider the Corvair heads for the 95/110hp versus 140hp engines sufficiently different, since the intake manifolds were integral?
The 95/110 heads had one carburetor each and exhaust manifolds with small diameter ports. The 140 heads had two carbs each and exhaust manifolds with larger diameter ports.
Staxman may have missed the most obvious choice. The SAAB 900 H-engine. Introduced in 1981 as a redesign of the 2.0 B-engine, it removed the dummy driveshaft. The distributor was moved up to be driven off the end of the camshaft and the water pump became a conventional belt driven unit. It was originally offered in an 8-valve SOHC head with or without turbo. MY 1985 introduced a bigger change.
The 1985 Turbo introduced a new 16 valve DOHC head while the (US market) 900 and 900S retained the SOHC 8V head. MY 1986 had the 900S upgrade to the 16V head w/o turbo. Three models, three different ( but related) engines. 900-8V NA SOHC ,900S-16V NA DOHC, 900T- 16V DOHC turbo. All based on the same H-type block.
The H-type block soldiered on until the end of OG9-5 production. There were some intermediate design changes as it was fitted to the OG 900 and the OG 9-5 as well as the 9000. To my knowledge, it’s still being used by BAIC who bought the OG 9-5 production design from GM. It’s a radially different car on the outside but open the hood and the origin is obvious. Very familiar to any OG 9-5 owner.
L-head and OHV versions of the venerable Continental 226 CID six, used by Checker from 1959 to 1962, as per PN’s article today. Who knew?
https://www.curbsideclassic.com/blog/engines/1959-1963-checker-continental-ohv-226-six-the-most-forgotten-post-war-engine-can-anyone-find-any-pictures-or-more-information-on-it/