300 cam selection

I'm building a 300 4V motor and I'm looking for a performance cam and lifter kit that will perform well with the 10.25 compression. Otherwise a stock rebuild. Thanks, OJ

 

Most SSB cams are run on a 110 degree LSA and the intake lobe center is set at 106 degrees ATDC.
Using this spec the smallest intake advertised duration while keeping the DCR under 8:1 is 284 degrees.

A 288 or 290 cam would give you a better margin for pump gas octane but you give up low end torque
and are better suited if there is some port work to the heads to extend the power band.
Otherwise you just end up with a narrow power band

That leaves you with the TA 284-88, 223/230 duration, 475"/475" lift with a 1.6 ratio rocker as the smallest TA cam possible.

Crower 50223, 220/226 duration, 488"/501" lift with a 1.6 ratio rocker, 112 LSA.

Paul

 

I didnt know T/A made 215/300/340 camso No:

 

The catalog seems to suggest they do.
Will have to call to find out.

 

are they iron heads ?

 

Okay. back to square one. Tore down the 300 block and it's junk. So I'm back to the 340 9.5 compression ratio motor.
Tried the suggested TA number but it doesn't show up on the online catalog. So I'll try the Crower # next. FYI. Using cast iron heads. Now I'll be needing a 340 4V intake if anyone has one. Got a Carter AFB. Selling the 300 4V intake if anyone is interested. Thanks, OJ

 

Isky has a good selection of 215/300/340 cams aswell:TU:

Hard to go wrong with the Cam-Father.

 

the 300 4v intake brings good money there hard to find. i just did a 340 built i put in a 216 intake-224 ex cam duration. that cam is plenty big for mid and top end. if you want a lot of bottom and dont care about 1/4 mile times. go with something 1 size smaller like 212 intake- 218-220 ex, just food for though to kick around

 

So why is the 300 junk? Is it cracked,or.........what's wrong with it? I'm curious because I might need one if it is already bored to much,and not cracked would be perfect for me to play with.(contemplating 4"bore wet sleeves)


And if you're going to do a 340,then a set of 73 or newer sbb 350 cap screw rods would be a good upgrade for your 340.

 

wish i knew about 350 rods before my built, no mods to do? are they forged?

 

Unfortunetly they're not forged, But they are a stronger design becuase of the bolt goes in the bottom with the top half of the rod has the threads,lets just say they are the female rods,because
they aint got no nuts.:Brow: And no,there isn't any mods that need to be done for these rods to work,but upgrading to ARP 8740 bolts is recommended for performance applications,and some beam polishing,there are other threads here that will go into more detail about sbb 350 rod prep,by doing a search.

If you really want to go crazy,about a month ago or so I posted some after market forged 4340 H-beam rods and the pistons that they would work with. Those rods would need some minor machining to make work though,and the rod journals turned down to 1.888" on the crank,one of the sizes NASCAR uses.(but they were not NASCAR rods) The C to C distance was 6.460" if I remember correctly(a stock 350 rod is roughly 6.385) And the pistons were Buick V-6 super charge pistons.This combo would work for 340s and 350s,and give a better rod ratio,and possibly a lighter rotating assembly,and modern rings.The bad part was the rods were a little pricey,the pistons,not to bad.

Heres the post;


http://www.v8buick.com/showthread.php?260092-Aftermarket-rod-possiblities-for-SBB-for-stroker-also

 

thanks for the info :TU:.if i do another one or the rods blow out of this one i will go with forged, the pistons are now forged so i think the rods are the weak link and then the crank.it pulls strong to 6000 rpm, but try to shift at 5500 rpm, might not hold up to long.

 

Thanks you Madman. Isky #621270 looks good.$159.00 Shipped from Summit

---------- Post added at 01:16 PM ---------- Previous post was at 01:02 PM ----------

 

Just givin some love to ol' Ed:3gears:


Remember that youll need old style lifters made for solid pushrods.

Some places will sell you a set of '70-up lifters without knowing betterou:

 

the isky cam on a 109 LSA will work good in the 340. even a 108 LSA would of been good

 

Question was asked. why is the 300 junk?

 

It depends on what type of power OJ wants.

What Larry is talking about is: If you want to make horsepower with the stock Buick 340 heads,
the exhaust duration needs to be at least 10 degrees more
than the intake duration or a combination of more lift and more duration.

Kind of a rule of thumb: when the ratio between the intake port flow to exhaust port flow is less than 75%,
the exhaust side needs extra help in order to evacuate the exhaust volume being produced by combustion because of the better flowing intake side.
The help comes in the form of more exhaust duration or more valve lift or both.
The less the ratio is from 75%, the more you need to cater to the exhaust side.
Unported stock Buick heads have a low ratio.

This is all for the sake of making horsepower which is increased torque at the high end of the power band.

If you opt for a single pattern cam the power drops off earlier than a with a split pattern cam but with the decrease in valve overlap and the later closing exhaust valve, the single pattern will give a better idle and more low end torque.

So the question to OJ is: What type of performance are you looking for?

Paul