We presently own a 84 Jag XJS 2 dr coupe and want to swap out the v-12 for a small block 350 chevy engine. I want to make sure that we get a 4 bolt main. What is the best way to insure that the engine we buy is a 4 bolt main? Is there a list of vehicles anywhere that can tell us what vehicles came with the 4 bolt main 350 small block? What is the best way to approach an engine rebuild to get up to 400 HP? Any help would be greatly appreciated. Thanks, Lee Armistead, Ruskin, Florida, Colts Fan:rolleyes:

no sure fire way other than pulling the pan and physically looking for the 3 center main caps having 4 retaining bolts on each of those caps.

alot of the 010 blocks did,, and some of the 379 blocks did. but it's not a for sure thing just by casting number. there are a few others too. but i'd look to be sure. don't buy if they won't let you pull the pan first. my 2 cents

IMHO a 4 bolt main is not 100% needed.. I'm running a 2 bolt ARP studded main 350 and in my 1988 camaro running 11.40's @ 118 mph, pulling the front wheels a few inch off the ground on launch.

To answer you questions though.. Like 74rat said.. You will have to remove oil pan to see if its a 2 or 4 bolt main. No other way.

To get the power your wanting.. You will need 9.5:1 to 10.25:1 compression. Don't go too wild with the cam and end up killing low end torque by over camming. Something in the 216/228* @ .050" to no more than 220/232* @.050".
Heads will be your biggest power gain. I would step away from all the older GM heads and go straight to GM vortecs or aftermarket.

Small block chevies have an engine suffix code stamped on them. The code is located on the front passenger side of the engine on the deck of the engine. You usually look down behind the alternator to see it. This is supposed to tell you what the engine was built to be. It often indicates 2 or 4 bolt main caps.

The problem is that some engines are "2 or 4" bolt mains... :rolleyes:

Once you find a candidate 350 casting#, Google "SBC engine suffix" and start looking to see what you have. With that said, I always pull the pan to double check...

Not exactly, the suffix is only going to tell you what the engine was originally installed in, and it's matching VIN number, not much else. Sure, it it was installed in a 5 ton dump truk, or a late 60's muscle car, you have a better chance of it being a 4bolt. But the suffix isn't going to tell you much else. The casting number behind the drivers side head (above the bellhousing bolts) is what your thinking of. But is not a foolproof indicator.
The casting number is as close as your going to get and even then, the only way to tell 100% for sure is to pull the pan. MANY castings that say 2bolt have been assembeled and installed in a chassis with being machined for 4 bolt main caps, and vice versa, anything your find that 'says' it's a 4bolt main,,, could not be. I know of one member right here on this board that bought NEW a late 60's car with a 327. When he pulled the motor down for a rebuild decades later,, it was a 4bolt 327. I defy you to find ANY listing for a 4bolt 327 casting. They don't exist,,,, but he drove the car off the dealership lot with one <shrugs>
Mortec has the most comprehinsive listing of SBC casting numbers and an indication of what you might find under the pan.

http://www.mortec.com/castnum.htm
Go by casting numbers is going to get you possibilities to check, and that's all.

With that out of the way,, the GM sbc with 4bolt mains is rated at 350 HP according to GM. And like said already,,, there are literally tens of thousands of 400+HP sbc's out there running 2bolt main caps. The extra two bolts are a little added security that your not going to drive over the crankshaft some day, but don't get too hung up on the number of bolts. Competant, quality machine work and meticulous assembly is worth a hell of a lot more than 2 extra bolts in 3 of the main caps.

lee, hit jagsthatrun.com for swap parts for that jaguar/chevy combo.
they have a worthy book, too.

Speed, thanks for the input, I'll check them out. Lee

Nightrider, Are you suggesting a cylinder bore with highrise pistons? How about chrome cylinders and crank journels? I have little knowledge on Cams, what have you found that does a good job for a street machine? Thanks, Lee

74Rat, somehow I just knew this wasn't going to be easy. I just believe that if I'm going to do this I want to do it one time, the right way and use the best engine block available. The thought of running over my crankshaft dosen't thrill me either. Hard part about all this is the guys that want to sell engines still have them in the vehicle, guess I'll invest in a battery power speed wrench fitted for oil pan bolts and lots of hand cleaner. Thanks, Lee

Lee... Yeah truthfully in my opinion it's not worth the trouble just to stick in a used engine.. If your gonna do a Jag swap then rebuild the chevy 350 from the start..

So if your getting a used engine from another car, junkyard, etc.. I would take it apart.. Number the main caps 1-4 with a steel stamp set (5th one don't have to number, no way of getting it mixed up with the others.

# each rod cap and rod with steel stamp set for the cyl it came out of.. (driver's side front to rear is # 1, 3, 5, 7.... Pass side front to rear is 2, 4, 6, 8)

Now take the block to a local machine shop and have them to measure the bore and tell you what they think it will need to be bored out too. Also take the crankshaft with you and have them to look at it and tell you if it need polishing or turning.. If so what undersize bearings will you need for it, and the price to have it done.. The shops around here are charging $90-125 to turn a crank now.. IMO if it's $100 or more I would just buy a new scat 9000 crank for around $160-170

Have the machine shop to hot tank clean the block, magnaflux it, if it checkes out good (no cracks) have it bored and honed to the min. size it will clean up at. Other machine work you will need done is frezze plugs installed, cam bearings installed, and old pistons pressed off and new pistons put on rods.

Or you could buy an already machined, ready to rebuild 350 4 bolt block from competition products for $500 that has the brass freze plugs and cam bearings in it, bored your pick of .030" or .060" over. http://www.competitionproducts.com/prodinfo.asp?number=BROOM-PMB350-030

Oh yeah if your gonna turn some over 5500 RPM with the engine I would upgrade the rod bolts.. ARP rod bolts and have machine shop put in new bolts and resize the big end of rods... Which will run around $90-100 for machine work and bolts.. If your gonna do that then you might want to just buy the rod option in the rebuild kit for $120. It's GM rods with ARP bolts, resized, etc

Order your rebuild kit.. For what your wanting www.northernautoparts.com has the best deals on rebuild kits.

With the Northern auto kits the base kit is $170 but you can upgrade parts for high performance use..

Here's what I would get, and what I have used in my engine now and some I have built for people.

This kit $170 http://www.northernautoparts.com/ProductModelDetail.cfm?ProductModelId=380

With these upgrade options..
Frost Plugs: Brass $9.40 (You won't need these if you buy the ready to build block cause they have the brass plugs in them already)

Cloyes Double Roller Timing:Cloyes Double Roller 3 Key-way C3023XSP $10.79

High Volume: Oil pump (must use oil pump shaft with steel pin sleeve) $8.63

Camshaft:Crane Powermax Cam & Lifters 2000-5000 RPM #113942 272/284 adv duration .454/.484 lift Valve Springs must be changed, Not Computer Compatible $120.88

Hypereutectic Pistons:Hypereutectic Pistons (flattop) # H345NP $19.96

Moly Rings: moly $11.74

Oil Pump Shaft: High Volume Oil pump shaft (must be used with high volume pump) $6.99


And if you go with a new crank get this with the rebuild kit.

New Crank: Scat New Crankshaft Cast/Steel #910442 2 Piece rear main $164.99


Along with that use an edelbrock RPM intake or Holley 300-36 intake, 600 to 750 cfm carb.

Heads is another thing.. Theres so many options on heads it would be hard for me to list them.. GM Vortecs are the hot street head now days but needs mods to work.. You could wait till you get your engine and check to see what heads you happen to get on the engine and post back then .

Also with the heads depending on what you get/buy you might need to change valve spring unless you buy a new aftermarket set of heads

:screwup: Thank you for your expertise. Years ago I had my 79 vette L-82 balanced and blueprinted, cost me about $1200. I suppose buying a completed engine from an expert makes a great deal of sense. I'll provide you with an update on the head situation when I know more. Thanks again, Lee.Lee... Yeah truthfully in my opinion it's not worth the trouble just to stick in a used engine.. If your gonna do a Jag swap then rebuild the chevy 350 from the start..

So if your getting a used engine from another car, junkyard, etc.. I would take it apart.. Number the main caps 1-4 with a steel stamp set (5th one don't have to number, no way of getting it mixed up with the others.

# each rod cap and rod with steel stamp set for the cyl it came out of.. (driver's side front to rear is # 1, 3, 5, 7.... Pass side front to rear is 2, 4, 6, 8)

Now take the block to a local machine shop and have them to measure the bore and tell you what they think it will need to be bored out too. Also take the crankshaft with you and have them to look at it and tell you if it need polishing or turning.. If so what undersize bearings will you need for it, and the price to have it done.. The shops around here are charging $90-125 to turn a crank now.. IMO if it's $100 or more I would just buy a new scat 9000 crank for around $160-170

Have the machine shop to hot tank clean the block, magnaflux it, if it checkes out good (no cracks) have it bored and honed to the min. size it will clean up at. Other machine work you will need done is frezze plugs installed, cam bearings installed, and old pistons pressed off and new pistons put on rods.

Or you could buy an already machined, ready to rebuild 350 4 bolt block from competition products for $500 that has the brass freze plugs and cam bearings in it, bored your pick of .030" or .060" over. http://www.competitionproducts.com/prodinfo.asp?number=BROOM-PMB350-030

Oh yeah if your gonna turn some over 5500 RPM with the engine I would upgrade the rod bolts.. ARP rod bolts and have machine shop put in new bolts and resize the big end of rods... Which will run around $90-100 for machine work and bolts.. If your gonna do that then you might want to just buy the rod option in the rebuild kit for $120. It's GM rods with ARP bolts, resized, etc

Order your rebuild kit.. For what your wanting www.northernautoparts.com has the best deals on rebuild kits.

With the Northern auto kits the base kit is $170 but you can upgrade parts for high performance use..

Here's what I would get, and what I have used in my engine now and some I have built for people.

This kit $170 http://www.northernautoparts.com/ProductModelDetail.cfm?ProductModelId=380

With these upgrade options..
Frost Plugs: Brass $9.40 (You won't need these if you buy the ready to build block cause they have the brass plugs in them already)

Cloyes Double Roller Timing:Cloyes Double Roller 3 Key-way C3023XSP $10.79

High Volume: Oil pump (must use oil pump shaft with steel pin sleeve) $8.63

Camshaft:Crane Powermax Cam & Lifters 2000-5000 RPM #113942 272/284 adv duration .454/.484 lift Valve Springs must be changed, Not Computer Compatible $120.88

Hypereutectic Pistons:Hypereutectic Pistons (flattop) # H345NP $19.96

Moly Rings: moly $11.74

Oil Pump Shaft: High Volume Oil pump shaft (must be used with high volume pump) $6.99


And if you go with a new crank get this with the rebuild kit.

New Crank: Scat New Crankshaft Cast/Steel #910442 2 Piece rear main $164.99


Along with that use an edelbrock RPM intake or Holley 300-36 intake, 600 to 750 cfm carb.

Heads is another thing.. Theres so many options on heads it would be hard for me to list them.. GM Vortecs are the hot street head now days but needs mods to work.. You could wait till you get your engine and check to see what heads you happen to get on the engine and post back then .

Also with the heads depending on what you get/buy you might need to change valve spring unless you buy a new aftermarket set of heads