6 of America’s smallest big-blocks and biggest small-blocks


Engine displacement, calculated in cubic inches or liters, is merely a function of two measurements: bore area (how wide the hole for the piston) and stroke (how far the piston travels inside the engine block). An increase in either of these will result in more “room” for air and fuel to combust inside the engine, and as we know, more displacement generally results in more power.

This is a companion discussion topic for the original entry at https://www.hagerty.com/articles-videos/articles/2018/09/24/6-of-americas-smallest-big-blocks-and-biggest-small-blocks


Olds 403 worthy of a mention. 6.6L and bigger than the Olds 400 big block (tall deck)


How about the small-block Chevy 400’s? I built and ran several of these in the day. Lots of inches in a very small package.


How about the Cadillac 501?


Certainly the GM LS series of engines share the 4.4" bore spacing so considered a small block but we know that the original Chevy small block extended from the original 265 2 barrel carb to the 350 ci 370 hp LT-1 in the 70 Corvette and the 327 ci Rochester FI 375 hp.


Thanks for the suggestion! I’m not hugely familiar with the Buick/Olds/Pontiac engine hierarchy but will certainly keep this in mind if I do a follow up story on the subject.


The Cadillac 500 is definitely big cubes in a small package! From what I understand, Cadillac didn’t really differentiate their engines as big blocks and small blocks as most of their OHV V8s shared a common architecture. I decided to go with the choices above as the manufacturers were very clear in defining their big and small blocks.

With that said, I’ll keep the 500 in mind for future V8 stories. Perhaps a history of factory 500+ cubic inch mills?


Chevy’s 400 small block was definitely on my radar for this story, but the LS7 edged it out by a little bit in cubic inch department. They certainly have a lot of potential!


Very interesting subject. I’m especially fond of the “little big block” component as most of these engines are relegated to the shadows of their bigger siblings within the pages of history.

I’d happily take a Ford 370 with a 2 bbl carb for a smooth and torquey setup.


How about the AMC 290, 343, 390 and their tall deck brothers 304, 360 and 401? Had a 380 in my original Javelin back in 1968 and now an expanded to 430 401 in my current project. External dimensions are the same, engine size cast into the block to thwart fraud.


And let’s not forget the Pontiac 400/400 RamAir series that went into the F body Firebirds.


Does the Chevy 502 crate count?


Actually, Ford’s original big block in the series was 352 c.i. big block. It shared the same block with the 390, 429, and 460. I had a '64 Galaxie XL with the stock 352 and swapped it with a 390 335 hp out of a '66, and later had a '69 T-Bird with a 429 Thunderjet. Never heard of the truck engine.


I also like to comment when I think that AMC has been overlooked. I am sure that the 1969 SC/Rambler 390 Ram-Air surprised more than a few people back in the day. It was almost drag strip-ready right from the factory just like others from the big 3, it just needed some slicks. Don’t forget the 50 or so Hurst prepared 1969 Super Stock AMX’s built especially for drag racing with the 390 with twin Holley carburetors and Headers by Doug. No warranty was available with those cars.


Actually, Ford’s original FE style block was a 332 in '58. The 352 was also available and was a quite powerful “Police Special” option. The block style was used for the 332, 352, 360 (truck), 390, 427, and 428. The 429 and 460 share no characteristics with the FE.


Carstanso took the words right out of my mouth. The FE also lived life (a fairly long one) as a medium duty offering in sizes like 361. I have my number match 352 to rebuild one day but I’ll stick with the 390(395 now at .030+) as I rather abusing it in my 64 galaxie for now. I’ve always wanted to do a well over square FE with a 332 crank and +60 390 bore, lands right around 357ci; I think it would be just about right for a pair of Garrets on inboard waterlog manifolds


You totally blew it by not reviewing the 1970 351 Cleveland!


The article is biggest small blocks not necessarily the best. Ford offered larger small blocks than the 351C, even though they’re universally agreed on as not being as good performance wise.


@jeffboncutter Technically the 429 and 460 are form the 385 series, the 390 is from the FE platform. While many would consider the FE a “big block” one could make a strong case that it is actually a “mid block” like a Pontiac or AMC, especially since the bore spacing and deck height limited displacement to around the 7.0L area(obviously we have stroker kits now) but my understanding is that the 385 was introduced in order to allow for more displacement this making it Ford’s true big block by having the largest block architecture and bore spacing.

Probably nit picking, but the choice isn’t necessarily wrong and in my opinion the FE technically isn’t either, it is a big block for it’s time when compared to the Windsor blocks. Trouble is that Ford offered way too many configurations of the big, small, and mid block configurations with many generations overlapping. I don’t think that either choice of the 370 or FE is technically wrong.


A little correction here regarding the Ford 351/400. The 400 was the M, modified, series engine and quite different from the Cleveland series engines just as the Windsor, engine is its own unique engine derived directly from the 289/302 small block. The Windsor came first in 1969. In 1970 the 351C was introduced with unique canted valve cylinder heads much like the Boss 302 heads introduced in 69. The 351/400 M engines were introduced in 73 or 74 and although looked like a Cleveland engine and had canted valves they were much different. Going back to the Cleveland the 2BBL and 4BBL heads were different and you could not put a stock 4BBL manifold on a 2BBL engine. The Cleveland would also bolt to the 302/351W bell housing and used the same motor mounts. The 351 M engines would bolt to a 429/460 bell housing and used different style motor mounts than the Cleveland. The M engine and 429/460 starters would interchange but not with the Cleveland engine. That said swapping a Cleveland with a Modified engine was quite a job and not worth it but swapping 351/400M to a 429/460 was easy and gave big horsepower gains. The modified engine was not a performer although I had a 400M in my Mercury Cougar wagon with adequate performance and able to spank an Audi Quatro Turbo without trying. Economy was a joke getting about 14mpg doing the legal 55mph on the interstate. But these engines were built for higher speeds so when speed limits raised to 65 the mileage went to 16.5mpg. I sold it before legal speeds got any higher but believe the car would probably max out at 18 at a little higher speed. Also I lived in Colorado at the time and that engine loved the 10% ethanol that was optional at some stations improving my daily commute mileage from 10mpg to 12 mpg.