What size engine should I get (302, 308, 310)

[bad68coupe]

howdy ya'll, I have just gotten to the point of my build to where i can start building an engine. I know I want to go with a 302 basis, but my question is what are the advantages and disadvantages of going with a 308 or even a 310? Should the size affect what cam I buy?
I am building it from a shortblock up and so i can get whatever parts I need but i was just wondering if anyone has had experience with any of these sizes.
Thanks guys

 

[callys]

No point in boring it bigger than it has to be (that's where the extra cubes come from), that just limits you on future rebuilds. 8 cubic inches would not affect parts choice.

 

[Hack]

You want 302 if possible, so that your block will be strong.

 

[thumper460]

Look into stroker kits.. 331 or 347 are actually pretty close to what you were going to spend on the bored out 302's.. just a thought..

Just me..........................

Thumper

 

[rbohm]

a few cubes wont matter. i also would go with a stroker if you are looking to get more displacement. 302 to 306 means nothing. 302 to 331 means about 25hp roughly for otherwise identical specs.

 

[Sicarius428]

Before boring out too much I would look into stroking it first.
Kevin

 

[BullittStangV8]

331 or 347 gets my vote if you want to more/stroke it. If your in there, you might as well do it?

 

[Steven Rupp]

It's true.. if your buying rotating parts then a stroker costs very little more to build. Stay close to 302 or go big with a stroker.

 

[bad68coupe]

sorry what i forgot to specify earlier is that it will cost me the same to get a 310 as a 302 and stroking it will cost alot more than $0.00

 

[blown65]

sorry what i forgot to specify earlier is that it will cost me the same to get a 310 as a 302 and stroking it will cost alot more than $0.00

I'd stay std bore or if needed bore .030. Its not worth it to gain the 8 CI IMO. Like others have said, you could always go .040 or .060 if needed down the road if something happens. If it doesn't need bored, stay std then.

If your going to make 1hp per cuinch your only gaining 8 hp. I doubt you would ever know it.

Now, if your buying some better quality parts like forged pistons then I'd go for the .030 variety. Reason being, if you decide to change to a stroker or a completely different setup down the road, your going to be able to sell 030 pistons much easier than std bored or 040 and 060 pistons.

 

[bad68coupe]

I guess what i was just kinda wondering was if i did lets just say, the 308, would that longer bore make the performance parts that i will put in the engine, more efficient? I figure the 302 stroke with performance parts is great, but then to have the 306, 308, 310 stroke would make those parts even better. I am jsut really thinking out loud, and don't really know the physics of it all, its really just theoretical

 

[thumper460]

Well then this is a math thing?? Cause, if you stroke for the same cost as you are going now ( Pistons/rods/ crankshaft) there is no contest!! IF you are keeping the 3.00 stroke and just boring the block... the 8 ci isnt worth the HP/Cost gains.

Say you get 400 BHP on a 302!! You will have 430 on a 347!! Cost for the 302 is the same as the 347 as far as block prep.. the rorating assy is the differance... if you keep all the stock stuff ( save pistons) then the add'l is what... 250-450.00 for pistons?? If you go to Hbeam ( or I beam) cost is the same.. new crank or stroker crank.. the cost is the same..... new pistons.. stroker pistons... the cost is the same!! cool//

SOOOOOoooooo.... as said.. this is a math thing?? Yes!?? Have fun..

Just me..............................

Thumper

 

[D.Hearne]

I guess what i was just kinda wondering was if i did lets just say, the 308, would that longer bore make the performance parts that i will put in the engine, more efficient? I figure the 302 stroke with performance parts is great, but then to have the 306, 308, 310 stroke would make those parts even better. I am jsut really thinking out loud, and don't really know the physics of it all, its really just theoretical

You're misguided here in your thinking. All these three engine sizes ARE the same stroke. The bore or overbore rather, is different. A 302 has a bore x stroke of 4.00 x 3.00, a 306 is a 4.03 x 3.00, a 308 is 4.04 x 3.00, a 310 would be 4.06 x 3.00. Listen to the advice the others have given you There was a 3.1" stroker for the 302, but it's a rareity today.

 

[86bluecobra]

I would not bore more then you have to. 30 overbore is plenty. Personally if I had a 68 I would be looking at a big block and not playing with small blocks. I would like to build a big block for my current mustang but if I had a classic it would definetally get a BBF.

 

[D.Hearne]

A stroker Windsor or Cleveland would be my choice, you'll have the best of both worlds. Easier to work on, lighter and have the torque of a big block. All that's based on starting with a small block 67-70 to start with. If it was a big block car already, then an FE would be the way to go

 

[mikethebike]

Here is the engine we are going to put in the FF kit car:
1. Dart II Sportsman block
2. Dart II cnc iron heads
3. Forged 3" crank
4. Crower 400 cid SBC rods with 280,000 psi bolts
5. High silicone content Keith Black pistons
6. Whatever cam Dart says will max power at 7500 and then die
7. Gear drive cam
8. Don't know the name but it's that after market mass air flow fi system (he already has it)
9. Full roller rockers
10. Titanium intake/sodium filled exhaust valves.

 

[Soaring1]

howdy ya'll, I have just gotten to the point of my build to where i can start building an engine. I know I want to go with a 302 basis, but my question is what are the advantages and disadvantages of going with a 308 or even a 310? Should the size affect what cam I buy?
I am building it from a shortblock up and so i can get whatever parts I need but i was just wondering if anyone has had experience with any of these sizes.
Thanks guys

If you have to start with buying an engine, and not overhauling one that you already own, then I would also recommend a 351 and stroke it. That will be all the power you will ever need and a lot of fun to drive. If you are going to stick to the 302 block, then stroke it for almost the same price as a standard overhaul.

 

[thumper460]

Here is the engine we are going to put in the FF kit car:
1. Dart II Sportsman block
2. Dart II cnc iron heads
3. Forged 3" crank
4. Crower 400 cid SBC rods with 280,000 psi bolts
5. High silicone content Keith Black pistons
6. Whatever cam Dart says will max power at 7500 and then die
7. Gear drive cam
8. Don't know the name but it's that after market mass air flow fi system (he already has it)
9. Full roller rockers
10. Titanium intake/sodium filled exhaust valves.

Christ.. it must be nice to have all that money for a 7500 rpm engine!!

Here is what we have and build today..7500 rpm shift points.
Stock early 302 block, w/ studs/ and stud girdle/ oil wind-age
Stock rods w/ arps bolts re sized / floated pins
forged light weight pistons .. lots of good choices out there
Stock 2M early crankshaft
Gear drive
Stainless steel valves , under cut stems, swirl polished
Springs for cam and titanium retainers
Induction.. intake for power from turns to top rpm of 7500-7800 rpm
Rotating assy balanced/ blueprinted/ block work the same/ crankshaft the same..
Heads.. Ported GT40s with upgraded valve train and studs

We must have saved at least more than HALF the cost.. reliability is good for the full season and then tear down, just in weight on the block and heads.. we can be 50 HP less and still pull in the straights!! Yes?? Just another way to race on a smaller budget.. cool?? 302 cubes rock!!

Just me.........................................................

Thumper

 

[65ShelbyClone]

1.) I know I want to go with a 302 basis, but my question is what are the advantages and disadvantages of going with a 308 or even a 310?

2.)Should the size affect what cam I buy?

1.) The only difference between a 302, 306, 308, and 310 is the bore size. An .030" overbore will net 306ci, .040" = 308, and .060" = 310. Advantages Are maybe a couple horsepower and a few pounds of torque. Disadvantages are thin cylinders and potential cooling problems. Early 289 and 302 blocks can usually hold an .060" overbore, but it's unecessary to go that far for anything but damaged cylinders or maybe the second or third rebuild. I prefer to be conservative on an overbore.

2.) It will have very little bearing on what off-the-shelf cam you pick. A custom cam grinder will take it into consideration because it is part of the calculations they do, but you don't need to worry about it.

If your engine is a standard 4.00" bore right now and needs an overbore, just go with .030".