GT Into a GTP coversion

[GTP Dad]

Well said Bob! But that is the proper way to do that conversion!!! And what's the matter you don't trust the wife with all that HP in the GTP? Maybe she would like to make a little tire smoke for a change and smoke some of the local mustang crowd. Why should you have all the fun?

[BNaylor]

Originally Posted by GTP Dad

Well said Bob! But that is the proper way to do that conversion!!! And what's the matter you don't trust the wife with all that HP in the GTP? Maybe she would like to make a little tire smoke for a change and smoke some of the local mustang crowd. Why should you have all the fun?

You've got a good point there Lynn. Her auto insurance is cheaper than mine. I used to take her out to the dragstrip but she can't stand the smell of old burnt rubber or nitro-methanol fumes. Plus when I taught her how to drive over twenty years ago she ran into a pole with our Celica GT. I still remember. Big problem I have now is son #1 wants the GTP as a graduation present. He says I can keep his Alero.

[GTP Dad]

Tell him to save his money, trade the Alero, buy his own GTP and keep his hands off of yours. I am sure dad would enjoy helping him mod his! (As long as he pays for it!)

[wlkjr]

Originally Posted by bnaylor3400

Now thats funny. Interesting twist.

I've found myself to be in a unique situation. I can't speak for others. Whenever I want to see what its like owning or driving a L36 I ask my wife for the keys to her Regal LS. Its a L36. Plus it has a u-bend delete and a hi-flow CAT to boot. And if she wants to drive an L67 I give her the keys to my Regal GS. Of course, the L67 GTP is off limits. Now thats what you call an easy conversion.

If we could all be so lucky.

[richtazz]

My next Grand Prix will be a GTP. I absolutely LOVE my GT, but what guy doesn't want more HP? I think Bob has the best of both worlds. It's too bad GM never made a manual transaxle that would work behind the supercharged 3800. Now that's a conversion I would do whatever it takes to get done!!!!

[GTP Dad]

There is a young lady who lives in my area who has a manual in her GTP. She had it converted, I really don't know the details of what tranny she used or how much it cost but she did make it happen. I guess anything is possible if you have the time and money.

[richtazz]

I'd like the details on that one!

[BNaylor]

Originally Posted by GTP Dad

There is a young lady who lives in my area who has a manual in her GTP. She had it converted, I really don't know the details of what tranny she used or how much it cost but she did make it happen. I guess anything is possible if you have the time and money.

More info please, if possible.

[GTP Dad]

I'll have to speak with my son for more details, he knows who she is and he told me about the conversion. I will see if I can get more information and let you know.

[richtazz]

We're waiting with giddy anticipation Lynn......

[BNaylor]

I'm curious about the linkage and pedal mod for the clutch and make of the tranny to include clutch and bellhousing.

[GTP Dad]

It may be a while guys my son only sees her at car meets and I don't know when the next one is. I will let you know the details when I can.

[cloggins99gt]

Hate to aggervate people being that Im new and I have found these forums very helpful with my car. I have a 99 gt vin k and I did the l36 to L 67 swap Im a regular guy with common sense i changed over nothing at first turned over first try and ran witha miss changed crank sensor and bam done.being that a pissed competor came and filled my crank case with water Im off to do another build . personally guys that want to do the super charge deal its totally not worth it for around the same jingle you can get some heads bore it over and get a performance tuner. salvage yards salvage yards salvage yards for the majority of your needs its a gm engine so 4.3 heads fit off the blazers theres. i love my gt and I spend a hell of alot more time resaerching than i do turning my wrenches I cant afford a shop or brand new parts but Im getting the best out of mine for under 500 bucks. Ill probaly never get done.

[Stealthee]

You're replying to a 10 year old thread, but I will bite.

First, I am going to bet no competitor filled your crankcase with water. I'd put money that your lower intake manifold gasket failed and filled your crankcase with water.

Tuning a NA 3800 will not get you the same results as a supercharged 3800. No ifs, ands, or buts.

4.3 heads are not the same as the 3800. It's not like the old 350 stuff on a 305. The two engines have nothing in common other than both being in GM offerings.





As you can see by the photos a 4.3 has 13 head bolts per side, whereas the 3800 only has 8.

Boring the engine oversize will net you next to no horsepower, not to mention the 3800 can only be minimally bored. You can get a junkyard supercharged engine cheaper than it would cost you to overbore NA.

[cloggins99gt]

there's a lot to chew come down South Carolina when you get through I'll be happy to show ya how. I didn't say anything about the year.Read learn and appreciate thanks and your welcome Back to the shop fux this 4.3L (262 CID)
The 4.3L (262 cid) V6 is the last and most successful engine in the Chevrolet 90-degree V6 engine family. This engine was introduced in 1985 as a replacement for the 229 cid V6 in the full-size Chevrolet, the Chevrolet El Camino and Monte Carlo. It also replaced the 250 cid in the Chevrolet full-size trucks and full-size vans (including the mid-sized Astro) as the new base six-cylinder engine.

The 4.3L V6 has a 4.00-inch bore and a 3.48-inch stroke, identical to the 350 cid Chevrolet V8 engine. To create a true even fire engine, Chevrolet produced a crankshaft with 30-degree offsets between each rod pin. Consequentially, rod journals were increased to a larger 2.25 inches. The connecting rods used on the 4.3L are therefore unique to this engine, being 5.7 inches in length, but having the larger 2.25-inch journals. The 4.3L also used larger valves than the 229 cid V6, with a 1.94-inch intake valve and a 1.50-inch exhaust valve (also shared with the 350).[2]

In 1986 and 1987, the 4.3L engine saw engine design upgrades similar to the Chevrolet small block V8. In 1986, the rear main crankshaft oil seal was changed from a two piece to a one piece seal. Some 1985 model year vehicles would have a 1986 engine due to service replacement - cylinder blocks were shipped with oil pans.[3] 1987 saw new center bolt valve covers and hydraulic roller lifters.[4]

For the 1992 model year, the 4.3L had its block design modified to allow a balance shaft to be installed.[5] Even though the 4.3L is an even fire V6, the 90-degree block layout is not ideal for smoothness. The balance shaft on the 4.3L is installed above the top timing gear, and runs through the top of the lifter valley. It is gear driven off the timing chain, and therefore a new timing chain cover was designed for these balanced 4.3L V6s. Balance shaft engines do not have provisions for a mechanical fuel pump unlike the non-balance shaft motors which retained the cast in boss.

As of the 2013 model year, the 4.3L was still in production although the distributor was eliminated in the late 2000s where a coil-on-plug ignition system was phased in. The only vehicles using the 4.3L were the GMT900 light duty trucks and vans.

As of March 7, 2014, the last 4.3L engine rolled off the line at Romulus Powertrain. Mercury Marine, which sells its engines under the MerCruiser brand, developed a 4.5L V6 based on the 4.3L architecture using similar dimensions.
GM 4.3 L35 and LF6 SCPI
Major design changes to the 4.3L V6 for the 1996 model year. Like other small block Chevrolet V8s, the 4.3L engine received redesigned heads which had improved airflow and combustion efficiency. These heads are referred to as Vortec heads. Furthermore the 4.3L was upgraded to receive sequential port fuel injection. The fuel system uses six centrally mounted injectors firing into six nylon hoses with poppet valves leading to each intake port. This system was called SCPI (Sequential Central Port Injection). This 4.3L used a two piece manifold, with the upper half manufactured from a composite plastic and the lower half manufactured from cast aluminum.

The engine block was revised with structural reinforcing ribs up front eliminating the two freeze plugs (on the front and back) along with an alloy oil pan (for the S10, Blazer, and Jimmy). The 1996+ oil pan has 12 bolts where a 16 bolt oil pan from the earlier 4.3 does not interchange.

Crankshafts manufactured for the 1999 model year (to the end of 4.3L production) had a pilot hole depth of 1.410" when coupled to the LSx-based 4L60E, which had a redesigned torque converter pilot hub which is longer). The torque converter pilot hub is longer than the early 4L60E (similar in appearance to the 700R4 c. 1993-95) or the second generation variants (incorporating a removable bellhousing) with the GMT330 or 1996-2000 C/K series.

This engine came in two versions, the LF6 rated at 175 hp (130 kW) - 180 hp (130 kW), and the L35 rated at 180 - 200 hp (150 kW). Only the S-series pick-ups used the LF6, while the full-size trucks, vans and Blazer and Jimmy used the L35 version. The L35 was optional on the S-Series trucks.

Year Horsepower Torque Fuel System Compression Ratio RPO Applications
1996 170 hp (130 kW) at 4,400 rpm 235 lb·ft (319 N·m) at 2,800 rpm SCPI 9.2:1 LF6 5
1997–2002 175 hp (130 kW) at 4,400 rpm 240 lb·ft (325 N·m) at 2,800 rpm SCPI 9.2:1 LF6 5
1996–2002 180 hp (130 kW) at 4,400 rpm 240 lb·ft (325 N·m) at 2,800 rpm SCPI 9.2:1 LF6 6
1996–2002 180 hp (130 kW) at 4,400 rpm 245 lb·ft (332 N·m) at 2,800 rpm SCPI 9.2:1 L35 5
1996–2002 190 hp (140 kW) at 4,400 rpm 250 lb·ft (339 N·m) at 2,800 rpm SCPI 9.2:1 L35 3,4,6
1996–2002 200 hp (150 kW) at 4,400 rpm 250 lb·ft (339 N·m) at 2,800 rpm SCPI 9.2:1 L35 2
1996–1998 200 hp (150 kW) at 4,400 rpm 255 lb·ft (346 N·m) at 2,800 rpm SCPI 9.2:1 L35 1
1999–2002 200 hp (150 kW) at 4,600 rpm 260 lb·ft (353 N·m) at 2,800 rpm SCPI 9.2:1 L35 7 so both 90block same engine in a sense crank and pistons would be a wise change then move on to dealing with the bore and the water Jacket issue. I would love to stay and share my knowlegde but I have been insulted by a fool and my taste has been lost for this community. Psssss..Give you hint machine shop