Tweaking an 87 Olds 307 - opinions?

[skryla]

I'm not sure if this is the right forum.

I already have a BTR built Olds 496 500hp 600tq in my 72 442 Vert.

I have my 87 Olds 307 and would like to get more out of it. I have about $12k in my 72 engine and do not want to go to that extreme.

I want to keep the original block in the car and fairly stock looking under the hood. Similar to what I did to the 72.

What have you guys done to wake up your 307?

 

[King_V]

I've read in several places that the emissions-era Olds V8s have VERY aggressive timing, and are extremely sensitive to EGR. Even partial blockage will cause pinging, etc., and sometimes people back off the timing as a quick fix.

Better-than-factory exhaust might also help some. The 442 has the quasi-duals - though I've read that the factory-style mufflers are extremely restrictive. The V6 is corked by the factory single exhaust , I assume the 307 being bigger might find even the quasi-duals to be a little restrictive despite its low-revving nature, though that's just a guess on my part.

 

[83hurstguy]

I lightly ported my 5A heads with bigger valves, installed headers, had BTR grind me a custom cam (small for torque, shift at 5200 RPM)... 14.27 @ 93 mph if I remember right. Still on the computer. A looser 9.5" - 10" converter with 26-2700 stall helps a lot too. Could probably get more out of it if I wasn't going BBO.

 

[skryla]

I lightly ported my 5A heads with bigger valves, installed headers, had BTR grind me a custom cam (small for torque, shift at 5200 RPM)... 14.27 @ 93 mph if I remember right. Still on the computer. A looser 9.5" - 10" converter with 26-2700 stall helps a lot too. Could probably get more out of it if I wasn't going BBO.[/quote

83hurstguy did you do anything to help it brethe? Carb, Intake? Remove smog pump?

Does the hypertech chip do anything? Which one?

Again, I know what I am working with. Not expecting HUGE gains.

 

[83hurstguy]

I lightly ported my 5A heads with bigger valves, installed headers, had BTR grind me a custom cam (small for torque, shift at 5200 RPM)... 14.27 @ 93 mph if I remember right. Still on the computer. A looser 9.5" - 10" converter with 26-2700 stall helps a lot too. Could probably get more out of it if I wasn't going BBO.[/quote

83hurstguy did you do anything to help it brethe? Carb, Intake? Remove smog pump?

Does the hypertech chip do anything? Which one?

Again, I know what I am working with. Not expecting HUGE gains.

Carb is stock, but I rebuilt with bigger needle/seat (probably not necessary). Get the right thexton tools and rebuild it using the factory CSM so it runs right. I changed out the secondary needles and actually ended up slightly leaner than the factory DA's using a wideband gauge. I'd have to check notes to figure out what I ended up with... It was one of the Edelbrock needle sets that's available aftermarket, possibly CV's. You can also play with the secondary air pulloff valves and spring tension.

Smog pump is gone. True dual 2.5" exhaust with American Racing 1-3/4" headers. Too much header for the combo, but I planned on putting in a 403 at one time. 1-5/8" would probably be better.

Intake is an Edelbrock performer (NOT RPM). I used it b/c it has constant cross section runners, much more than the A4. However, cruise linkage won't work then, the EGR is flipped 180*, and the throttle bracket needed a little grinding. I'd considered keeping an A4 if you want all factory connections to work perfectly. I tried 1/2" carb spacers (only ones that clear hood with stock air cleaner) and didn't have any quantifiable luck at the track.

I still have functional EGR to prevent part throttle pinging... however, with the torque converter being loose, the engine won't lug enough to ping.

Never messed with a hypertech chip. Never seen someone with quantifiable positive results, and from looking at the spark maps years ago, the total timing didn't increase. Therefore, you are better off just bumping base up 1-2* to test it.

I run it without the air cleaner, seems to be worth 0.05. I never put the effort into a good ducting system to the dual snorkel though some people claim great results.

It really needs a bit more cam than I have, but I didn't want to turn more rpm in a cast piston bottom end with stock rod bolts that probably have 108k miles on them.

 

[King_V]

Will those same mods work? As I understand it, the non-roller 307 has heads and intake manifold more like a classic 350 Olds, but the roller motor has much smaller heads and intake manifold ports - and that the same sorts of changes may NOT help it.

Do NOT quote me on this - never dealt with it myself - but I understand that the roller was optimized to have all its power WAY down low in the RPM range.

True duals will help, but I imagine most headers available will be overkill for the small ports on those 7A heads.

 

[DoubleV]

From all accounts I have seen, the Hypertech chips for CCC cars are apply named. They are alot of 'hype'.

Are you looking to tear into this engine with new cam, head work and such or are you just looking for some simple 'bolt-ons'? With very minimal work, my stock 85 442 ran 15.54 @ 88mph on my only run at the track. More work could've easily helped too like maybe a small carb spacer or adding ducting to the 2nd snorkel. I achieved this with nothing more than a better exhaust ( still not even true duals ), removing that stupid restrictive ring from the air cleaner, removed the air pump entirely ( including the little tubes that protrude into the exhaust ports ), and removed the 2 restrictive tubes under the carb on the floor of the intake. Minor tuning like bumping the timing a hair and allowing the secondaries to open up quicker was done too. Keep in mind your heads and intake are different than mine.

A guy on Oldspower had an 87 442 with minor mods similar to what I have done and he was also in the mid 15's. With headers I think he was 15.3. Either way these changes will add some spunk to an otherwise bone stock 307.

 

[88hurstolds]

Here is a good write-up:

http://tlentz.oldsgmail.com/more_power.html

 

[Evan11]

You won't be able to swap your intake for a performer like he did on his Hurst/Olds, because the '85 up 307's had an intake of their own due to the smaller port heads they used.

 

[olds307 and 403]

Here are your issues, tiny port heads that flow 130/105 cfm stock, small roller can with piddly lift, less than 8 to 1 compression, awful factory exhaust and very aggressive timing. If your stuck on stock heads and block, they need much help. You will need custom pistons or a lot milling and max porting. Find a 72 350 with 7a heads and paint it black and build it how you want.