which would you prefer

[MrSony]

The 307, is not a bad motor. Not at all. Some even had factory roller cams and lifters! VIN Y and VIN 9 I believe The can be built up a little, but it's like the Chevy 305. Decent motor in stock form, can be built to be a bit peppier, but swaps are just so much easier and cheaper in the long run. Plus, it's literally plug and play. The blocks are exactly the same on the outside as far as mounting things like motor mounts and bracketry go. If you want good, reliable power with plenty (if you know where to look. SummitRacing has rebuild kits for the olds 350 for like 600$) then an Olds 350 or 403 (even more common than the 350) are the way to go. Plus, with the 350, you can use the heads and intake from an Olds 455 😀 It all depends on what you want to do. So, do you want a good reliable (again in stock/near stock form) motor, while still a V8, will never have the power capabilities of a 350, 403, 455 etc., or do you want to do a swap? If you got the time and $$$, it is a no brainer. But, it's your car. Do what you wish.

 

[theoldsone]

307 is never a strong enough engine
350 good tourqe, even better than a 350 sbc (don't tell anyone I said that)

Do what you want to do. Want to brag about a numbers matching car cool. Want to go fast cheap, cool.

 

[HOAdrian]

The Performer intake is pretty close to being an aluminum copy of the factory intake. Saves about 25-30 lbs over iron. I scored one from a junk yard for $35 so that's what's on the H/O now. The Performer RPM is taller with more meat around the ports for matching to BBO heads should you desire.

Externally, the 403 has the same dimensions as the other SBOs so it's an easy swap. Unfortunately, the 403 was produced at about the worst period of the smog engine era. The compression ratio is really low. Some 5, 6, or 7 heads and a cam upgrade will wake them up. Find some that have been ported (nothing radical), has the exhaust cross-overs filled, the big intake valves, bolt holes drilled out for 1/2 inch, exhaust divider welded up, and studs for adjustable rockers. You can find them for around $1000 a pair. The big bore in the 403 helps to un-shroud the valves. The nice thing about putting a 403 together is you can still drive your car around with the 307 until it is done. There are some guys running 307s in stock class that may be able to offer guidance on improving the performance.

You'll want to beef up the 200-4R to survive the increased HP. The 84 H/O has one of the more desirable 200-4R transmissions to start with. Dr Dan has a 200-4R upgrades thread over at RealOldsPower.com. He upgraded the transmission in my H/O, other than a billet drum. He drag races his 83 & 84 H/Os and he runs 403/200-4Rs in both.

 

[joesregalproject]

I like having cars all original but at the same time a car that was 'originally' slow isn't much fun. A good compromise of speed and originality might be an Olds 350 dressed in the 307's accessories. From the outside they pretty much look the same, one will drop right in place of the other, it's still an Oldsmobile engine, and it would easy to swap back.

 

[NicholasH\O freak]

basically the 307 can be built performance wise bigger then a stock 350. what would u have to do to get it to perform better then a 350.

 

[L92 OLDS]

i have 1984 cutlass hurst olds would u keep the 307 enginge or swap it for an olds rocket 350 or what

If your 84 Hurst is an extremely clean car with low miles I would keep the 307 in it and enjoy it the way GM intended. As Foxtrot eluded to, the 3:73 gears and 4 speed auto make it a fun car to drive if it is tuned and running as it should. Keep in mind that when you start modifying an old school carbed engine for big power you will lose driveability and fuel mileage. I put a 403 in my 442 and its been a fun car but I have to run premium in it and take it easy on 80 plus days to keep the temps in check. I've flown the Oldsmobile rocket flag for over 30 years but am now moving on to LS power. In my opinion technology is where it's at and my VVT L92 should net over 500 hp with good idle quality. Doc Watson would be proud. I have spent a small fortune on my 403 (heads, multiple cam swaps etc) and have run a best of 13.1. Putting small chamber heads on a 403 is a fairly easy and effective way to build power and get into the low 13 second range. Do a search or spend some time on realoldsmobile.com

 

[NicholasH\O freak]

what would you have t5o have done to the 307 to match the 350

 

[MrSony]

what would you have t5o have done to the 307 to match the 350

Basic hotrod type stuff. Headwork porting/polishing, new cam (some 307's, Vin Y and Vin 9 I think) came with roller cams and lifters from the factory but the heads were garbage. New true dual exhaust and headers, better carb/intake (can't go wrong with a well tuned q-jet 😀), toss on some roller rockers as well. The 307 isn't a bad motor, but like I said it's in the same line as the chevy 305 or the older 60s chevy 307. Yeah, you can make them perform really well for being little econo-v8s, but why? An Olds 350 would get you just as much power if not double if you got an EARLY 70s (upto 73 or thereabout) or late 60s block that is still in good shape.

 

[Jimmy]

mr sony so ur saying that what would u put in there then instead of the 307 i know that people rather have the bigger engine i kinda building a show i want the engine to be big but not a drag car you know what i mean its hard to explain i just have been turned in many directions and dont know what to do

I have a 84 Hurst also. In my opinion if you are not planning to make it a drag car and want to keep it as close to a show car as you can I would leave the 307 in it. They are not strong motors horse power wise and not really a motor to build. They are very solid though and run well if maintained. I recently had to rebuild mine due to a spun bearing (long story), but the engine had no wear when I tore it down. If you want to go the horsepower route, which I am doing with my 83 Hurst I would just do an LS swap. You can get a 5.3liter which is basically an LS motor with a cast iron block instead of Aluminum and build it to run. I don't know if this helps but I can tell you that the LS motor I am installing will about double the horsepower in the car and the fuel mileage will be better than it is now.

 

[Jimmy]

Here is a pic of a 5.3 fuel injected motor I am putting in a 67 Chevy truck.