my 455 sucks

[leojvs]

its so lame. My V6 has more power than it. 205 hp in a car weighing 2.5t ? Boring. Money is a tight issue, but I want more power out of it, obviously on the cheap. Its all stock at the moment, but will be getting a dual 2.5 inch exhaust, dumping near the rear wheels fairly soon. I have to keep the 76 heads as I am running LPG, and as these heads are suited to unleaded, they are suited to lpg. A change in heads means bye bye cheapo way of running car. Its on petrol too, which is a little more powerful than lpg, but not much. Any suggestions from you Guys and Gals here. Oh, its an Electra Limited T400. Should be in my profile. As it happens, just round the corner from my fire station there is a guy who services Olds, Buicks, Caddys etc. A very rare thing here in Oz.

Thanks

[rcull]

I expect one of the best places to get cheap HP is in your distributor. You can just get the stock one reworked so that you are doing as well as possible in the timing.

Here's a start...http://www.buicks.net/shop/reference/engine_timing.html

[bob k. mando]

I have to keep the 76 heads as I am running LPG, and as these heads are suited to unleaded, they are suited to lpg.

the 75/76 heads are open chamber with no squish area whatsoever. if you had one of the earlier heads, 67-74, or aftermarket alum's (expensive i know, but not any more than having port work done to factory irons) you can probably get both higher compression and better detonation resistance.

I have to keep the 76 heads as I am running LPG, and as these heads are suited to unleaded, they are suited to lpg.

???

i'm not sure what you're talking about. you mean that with the high nickel content iron heads you don't have to have valve seats installed? this applies to ALL Buick big block heads, not just the ones from 75/76.

LPG is typically much higher octane than pump gas so you shouldn't be expecting a detonation problem.

http://en.wikipedia.org/wiki/Autogas

[Wldcat 69]

Trash the whole deal and find you a 430,I've been runn'in them since 1985,some with God knows how many miles,useing unleaded 93 Amaco,now BP,a few moth *****,and Marvel Mystery Oil,they just keep on eating up the pavement on half the gas useage of ANY 455.Packing 360 stock horses,easily tweaked.Throw in a double roller Edlebrock chain,and keep your cooling system clean,you will take out any Roadwarrier!!

[bobc455]

What condition is your 455? Is it freshly rebuilt, or is this a 30 year old motor?

In either case, the first step is tuning. Try to get your hands on an "advance kit", and tune the initial timing as well as the advance curve.

Also, in general I have found that running slightly richer than stock will help performance, so if you have the Quadrajet you might try to get your hands on some fatter secondary metering rods.

A cam and headers can really wake these motors up too.

-Bob Cunningham

[sicksteve]

I agree with rcull. I have a '76 Riviera-that has stage1 heads on from the dealer when the car was bought new. And I have a '73 Riviera with a low-compression stage1 engine

A couple of months ago, I completely upgraded the '76' HEI ignition system. Originally I was going to replace the HEI for a MSD ready-to-run distributor i bought on ebay. But instead, I used with ACCEL's best in-cap coil ("Blue Thunder"), ACCEL' best 35367 high-current ignition module, new wiring harness, cap&rotor, ACCEL 300+ low resistance wires, R45TSX plus regapped @ 0.070". Optima battery Delco 12-SI alternator 2/0 battery cables. The '76 runs sooo much better now--crisper throttle response, better mpg and a noticeable improvement in power.

I has even better results with the '73 Riviera GS. It has a new stainless-steel 2 1/2" dual, Magnaflow exhaust system, an ACCEL 71105 "Billetproof" distributor with a similar ign. module (P/N 35366--same as 35367 for HEI,but smaller in size), a NOS Jacob's variable magnetic core Ultra Coil, more ACCEL 300+ wires, a new ignition switch with 10 gauge wire fused at the Optima battery, 2/0 battery cables and plugs gapped at 0.065". It also has ACCEL's oiled-foam low-restriction air cleaner. There was a tremendous difference: better throttle response, silky smooth idle, more torque, HP, mpg(Jacob's actually used to guarantee it--only if you open up the spark plug gap to get a hotter spark). My mpg went from 8.9 to 15.1!!!

These engines may be rated at 205-230net HP, but they're still very torquey.