Figured Id throw this out there I had a 350 block I was gonna build but came across a Free 305 in Great Shape.Now before this debate gets out of hand I now a 350 With 3k into it will more than likely outperform a 305 but in stock form and in trying to keep cost down I am debating just running the 305. My question is in stock form how much more of a difference am I looking at?

if your comparing stock to stock from the mid 80s to early 90s then your looking at 20HP differance at the most. I would use the 350 block since parts are all over the place for them.

THe block is out of a 72 malibu the 305 is out of I believe a 80's monte SS. Youre allowed to put any year 350 in but in stock form

does the engine have to be from a 82-92 Fbody or any GM vehicle?

Any gm vehicle up to 350 ci I had called the director to get clairification I could not run a 327 because it never came in my car but a 350 I can from any year.

6. Engines must remain stock to make, model and year car used. All rebuilding must retain all stock spec’s
and original replacement parts, No exceptions! GM engines may be used in Pontiac and Oldsmobile cars.
Maximum engine size per manufacturer: GM – 350; Ford – 351; Mopar –360. After-market steel or cast
aluminum valve covers with breathers permitted.
Note: Each engines specification will be referenced off the highest performance model in production in
relation to the family of car used by each team.

Im not understanding the netire rule here. Can you run a different pair of factory heads on any year 350 block? If you find 350 from a wrecked third gen then are you stuck using the heads that came on that engine or can you use something esle from GM?
How do they know what your running?

Im gonna be honest with you this is the grief I have with this division. The rules are not 100 % clear I attended the rules meeting and we could barely get a lift rule" which we finaly got .410 " and compression ratio rule we did not get a clear answer. The rule is suppose to be stock to year of car. Reading it. But its not being followed has written IMO

to answer you're question
My interpretations speaking with the race director is that you can use any 350 and its fine point blank but that leaves alot of different options ? Leading me to believe that you could run different stock heads. I find the rules very unclear many other pure stock division only let you run 305s with stock 305 heads which is fine by me fair racing

can any port work be done to the heads and intake at all? There are quite a bit of free hp mods that can be done to a typical SBC.

Not suppose to be in this division. Youre really not allowed to do anything for horsepower which is why I'd even think of using a 305.

Just has an example of head work done in higher division.The street stocks Which is a division above mine rules state

1.5 HEADS: Only stock O.E.M cast iron production. GM Vortec cylinder heads permitted as listed below. Multi
angle valve grinding permitted providing all cuts must be centered off centerline of valve guide. The bottom cut
not to exceed 1/2" into valve pocket. Maximum valve size 2.02” The intake and exhaust ports must remain in
their original "as cast" configuration. Any sanding, polishing, relieving, grinding, chemical treating, abrasiveblasting
alterations to the original form or addition of material to the ports or combustion chambers, will be
declared illegal

with the magic ninja engine work you'll need to do to be competitive you will get at least 50 horse more from the 350

There is a new claimer rule which is Probally good for the division where if you finish 2nd you can claim 1st places motor for you're motor and $800. This is suppose to keep it more competive which I agree but it restricts you building because you really do not want to exceed the $800.00 and chance losing you're motor

Another important tip is the 305 can have a 4 barrel carb, the 350 has to be 2 barrel.

I wasnt aware of that? according to my father you would need the 4 barrel because it wouldn't kick in tracks to short. But id def want to look into it. Joe ran a 305 in his car BTW ed

correction, I believe that is a Waterford rule. My bad

ah ok I wanted to run there a few wednesday nights but they do not allow Camaros

double check on that rule, just to be safe, but I think that was just a waterford thing now that I think about it. When I was shopping, I had both tracks in mind.

i would take a 350 block with 305 heads and 1.6 rr's and a small cam rolling some old school high compression sleeper

^^ That last statement is key. 350 parts are a dime a dozen. Since 305s are less widely used, the parts are more expensive.

What exactly is more expensive? They use the same heads, cams, intakes, rockers, lifters etc. Same waterpump, oil pan, timing cover/chains. the only thing different is the bore sizing/piston. They use the same cranks and rods even.



Thats what I said!

the only parts specific to a 305 are less expensive because they are undesireable.

there is a 9/5 compression rule ratio. we weren't giving a clear answer someone finally got it out of the director and that is what they said

Is this a new class or something? It sound slike they are making it up as they go along.

it's an amateur division they started a few seasons back. 1st is was called Pro Enduros, then Pure Stocks. Basically, it's your typical hobby stock division. Each track rights they're own rules, but the general idea is to get guys out of the demo cars and give them a chance to really race giving them the urge to move up into pro divisions at the track. Because it's supposed to be a "stock" car, but they want the cars to be competitive, the rules are very vague. Leaves the the ability to change as needed.

with how vague things are and such everyone will be cheating and if you think your gonna get the other guys motor you are nuts I would have a spare dead stock motor for the guy who thinks he is getting my motor lol

Why do they limit to a 350? I dont see why you couldnt use a 400 its a GM motor.

Re-reading the rule it only said max engine size is a 350.. so no overbores? Can you destroke a 400 to make 350 cubes and be good?

I think you gotta pull it there at the track.



wouldn't work if they decide to check the VIN in the block.

My block has no vin? The only way they could check is by the casting # and even some gmpp reman motors had none. But my point was it says 350 cubes not block

Good luck pulling a motor at the track. Something that just ran balls out around the track, you cant pay me to touch it.

Yea it sucks really cant take pride in a motor nowing someone could take it. I now I planned on building a pretty stock to the rules 350 with alot of security but done right With this rule Id be nutz has you stated