Preparing
an engine block for machining
The first
step in preparing a bare block is to get it
clean. Begin by scraping off any gasket
adhesive and the worst of the built-up
grease. Even with all of the right tools,
tearing down a block can test your patience,
and I recommend having the shop that's going
to clean the block also remove all of its
plugs. If you want to do it yourself, here's
how:
All of the freeze plugs need to be removed
with a hammer and punch. Pull them out with
pliers before you knock them all the way
into the water jackets. (Otherwise, since
they're non-magnetic, you'll have to keep
moving the block around until the plug lands
over one of the holes for them, getting a
grip on it with the pliers, and pulling it
out. This is how we learn humility.) Now out
come the oil gallery plugs, which have weird
square female heads that even with the
proper Snap-On tool still often have to be
carefully drilled out.
The lifter galley and the entire inside of
the block were then fully deburred to remove
all of the "pockets" where casting sand and
metal may come loose, something I'd suggest
to anyone building an engine. I used a die
grinder with emery cloth cartridges, which
makes it possible to reach into all of the
block's contours.
Once you've got the block completely bare
(except for the leaving main caps in the
right places) and deburred, you're ready to
call the local engine rebuilder and find out
when they're changing their solution so you
can get it in their tank when it's not full
of sludge. The shop I took the block to for
it to be hot tanked let me bring it in right
after they changed their tank's solution on
a Friday afternoon, and we lowered it in and
let it spend the whole weekend thinking over
how badly it wanted to hang onto the last of
its grease. Monday morning I was there early
to hoist it out of the tank, and spent a
full fifteen minutes running water all over
it and through all of the passages, ending
up with something that was clean. Then I got
an air line and got the entire block
completely dry, and it was ready for
machining. |
Big block Chevy bore and stroke
| Engine Size |
Stock Bore |
+.060"-over |
Stock Stroke |
| 366 |
3.935" |
3.995" |
3.760" |
| 396 |
4.094" |
4.154" |
3.760" |
| 402 |
4.125" |
4.185" |
3.760" |
| 427 |
4.250" |
4.310" |
3.760" |
| 454 |
4.250" |
4.310" |
4.000" |
| Mark 5 — 502 — Mark 6 |
4.468" |
4.530" |
4.000" |
| 454 Engines |
3.760" |
4.000" |
4.250" |
4.500" |
4.750" |
4.875" |
| Stock bore = 4.250" |
427" |
454" |
482" |
511" |
539" |
553" |
| Bored .030" = 4.280" |
433" |
460" |
489" |
518" |
547" |
561" |
| Bored .060" = 4.310" |
439" |
467" |
496" |
525" |
554" |
569" |
| Bored .090" = 4.340" |
445" |
473" |
503" |
533" |
562" |
577" |
| Bored .100" = 4.350" |
447" |
476" |
505" |
535" |
565" |
580" |
| Bored .125" = 4.375" |
452" |
481" |
511" |
541" |
571" |
586" |
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of Page 
| 502 Engines |
3.760" |
4.000" |
4.250" |
4.500" |
4.750" |
4.875" |
| Stock bore = 4.468" |
472" |
502" |
533" |
564" |
596" |
611" |
| Bored .032" = 4.500" |
478" |
509" |
541" |
573" |
604" |
620" |
| Bored .062" = 4.530" |
485" |
516" |
548" |
580" |
612" |
629" |
| Bored .092" = 4.560" |
491" |
523" |
555" |
588" |
621" |
637" |
| Brodix, Dart & Merlin Blocks |
4.000" |
4.125" |
4.250" |
4.375" |
4.500" |
4.625" |
4.750" |
4.875" |
5.000" |
| 4.500" bore |
509" |
525" |
541" |
557" |
572" |
588" |
604" |
620" |
636" |
| 4.530" bore |
515" |
532" |
548" |
564" |
580" |
596" |
612" |
628" |
645" |
| 4.560" bore |
523" |
539" |
555" |
572" |
588" |
604" |
621" |
637" |
653" |
| 4.590" bore |
530" |
546" |
563" |
579" |
596" |
612" |
629" |
645" |
662" |
| 4.600" bore |
532" |
548" |
565" |
582" |
598" |
615" |
632" |
648" |
665" |
| 4.625" bore |
537" |
554" |
571" |
588" |
605" |
622" |
638" |
655" |
672" |
To calculate the displacement of an eight-cylinder
engine: bore x bore x stroke x 6.2832
Cubic inches x 16.387 = cubic centimeters. Cubic
centimeters x .061 = cubic inches
The five
largest Bonneville Salt Flats engine classes
| AA / Fuel and AA / Gas |
501 cubic inches and over |
8.21 liters and over |
| A / Fuel and A / Gas |
440 to 500 cubic inches |
7.21 liters to 8.19 liters |
| B / Fuel and B / Gas |
373 to 439 cubic inches |
6.11 liters to 7.19 liters |
| C / Fuel and C / Gas |
306 to 372 cubic inches |
5.01 liters to 6.10 liters |
| D / Fuel and D / Gas |
261 to 305 cubic inches |
4.27 liters to 5.00 liters |
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BBC Engine block casting numbers
| Number |
Size |
Rated Horsepower |
Production |
Main Caps |
|
340220 |
427 |
|
1968-1976 |
Four-bolt
(tall-deck) |
| 346236 |
454 |
|
1975 |
Two-bolt |
| 361959 |
454 |
|
1978-1987 |
Two-bolt or four-bolt |
|
364776 |
427 |
|
1974-1976 |
Four-bolt
(tall-deck) |
|
364776 |
454 |
|
1977-1990 |
Four-bolt
(tall-deck) |
|
364779 |
366 |
|
1968-1990 |
Four-bolt
(tall-deck) |
|
473478 |
427 |
|
1977-1990 |
Four-bolt
(tall-deck) |
|
1014183 |
366 |
|
1991-1992 |
Four-bolt
(tall-deck) |
| 3855961 |
396 |
325 and 360 |
1966 |
Two-bolt |
| 3855962 |
396 |
360, 375, and 425 |
1965-1066 |
Two-bolt or four-bolt |
| 3869942 |
427 |
390 and 425 |
1966 |
Two-bolt or four-bolt |
| 3873858 |
396 |
375 |
1966 |
Four-bolt |
| 3902406 |
396 |
325, 350, and 375 |
1967 |
Two-bolt or four-bolt |
| 3904351 |
427 |
425 |
1967 |
Four-bolt |
| 3916321 |
427 |
425 and 435 |
1968 |
Four-bolt |
| 3916323 |
396 |
325, 350, and 375 |
1968 |
Two-bolt or four-bolt |
| 3935439 |
427 |
435 |
1968 and 1969 |
Four-bolt |
| 3935440 |
396 |
350 and 375 |
1969 |
Two-bolt or four-bolt |
|
3937724 |
366 |
|
1968-1976 |
Four-bolt
(tall-deck) |
| 3955272 |
396 |
325, 350, and 375 |
1969 |
Two-bolt or four-bolt |
| 3955272 |
402 |
325, 350, and 375 |
1969 |
Two-bolt or four-bolt |
|
3955274 |
366 |
|
1968-1976 |
Four-bolt
(tall-deck) |
|
3955276 |
427 |
|
1968-1973 |
Four-bolt
(tall-deck) |
| 3963512 |
454 |
360, 375, 425, and 460 |
1968-1971 |
Two-bolt or four-bolt |
|
3969852 |
366 |
|
1968-1976 |
Four-bolt
(tall-deck) |
| 3969854 |
402 |
360 and 375 |
1972 |
Two-bolt |
| 3969854 |
454 |
360 and 375 |
1972 |
Two-bolt |
|
3969858 |
427 |
|
1968-1973 |
Four-bolt
(tall-deck) |
| 3999289 |
454 |
|
1972-1979 |
Two-bolt |
| 3999290 |
402 |
240 |
1972 |
Two-bolt |
|
3999293 |
366 |
|
1968-1976 |
Four-bolt
(tall-deck) |
|
3999294 |
427 |
|
1968-1973 |
Four-bolt
(tall-deck) |
|
10114182 |
454 |
|
1992 |
Four-bolt
(tall-deck) |
| 10114184 |
427 |
|
1991-1992 |
Two-bolt or four-bolt |
| 14015445 |
454 |
|
1978-1987 |
Two-bolt or four-bolt |
BBC oval port cylinder head casting numbers
| Number |
Engine Size |
Year |
Combustion Chambers |
|
336781 |
454 |
1973-1985 |
Open chamber |
|
346236 |
454 |
1975-1978 |
Open chamber
("peanut" ports) |
|
353049 |
454 |
1970-1973 |
Open chamber |
| 3872702 |
396 and 427 |
1966 |
Closed chamber |
| 3904390 |
427 |
1966 |
Closed chamber |
| 3904390 |
427 |
1966 |
Closed chamber |
| 3909802 |
396 and 427 |
1966-1967 |
Closed chamber |
| 3917215 |
396 and 427 |
1966-1969 |
Closed chamber |
| 3931063 |
396 and 427 |
1966-1969 |
Closed chamber |
| 3964280 |
427 and 454 |
1966-1970 |
Closed chamber |
| 3964290 |
427 and 454 |
1966-1970 |
Closed chamber |
|
3993820 |
402 and 454 |
1970-1971 |
Open chamber |
|
3999241 |
402 |
1970-1972 |
Open chamber |
|
6272292 |
402 and 454 |
1971 |
Open chamber |
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BBC rectangular port cylinder head casting numbers
| Number |
Engine Size |
Year |
Combustion Chambers |
| 3856208 |
396 |
1965 |
Closed chamber |
| 3904391 |
396 and 427 |
1965-1967 |
Closed chamber |
| 3919840 |
396 and 427 |
1965-1969 |
Closed chamber |
| 3964291 |
396, 402, and 427 |
1965-1970 |
Closed chamber |
| 3964292 |
454 |
1970 |
Closed chamber |
|
3994025 |
454 |
1971 |
Open chamber |
|
3994026 |
454 |
1971 |
Open chamber |
|
3996074 |
454 |
1971 |
Open chamber |
|
6258723 |
454 |
1971 |
Open chamber |
|
6272990 |
454 |
1971 |
Open chamber |
|
