[69SJ4SPEED]

1) What is the CFM of the stock Quadrajet on the 69 428 in a Grand Prix?

2) The guy that sold me the car said that he had 66 heads put on it to lower the compression to burn 93 octane. They take AC's 44TS sparkplugs instead of the R45 that goes in the 428 heads that came on 69-74 428/455 heads. I'm learning Pontiac! What are these heads?

3) My fan to the A/C only has one speed. I wanted to change the Hi-blower relay (able to find) and blower resistor (can't find) as I'm told it is customary to change both at the same time. Anyone know where I can get one?

4) On my Dodge/Chryslers I've been able to buy Service / Parts / Body manuals on a CD-Rom for about $40 each from Detroit Iron. Their web site disappeared! I like these on CD-Rom as a can print the manual (I have a printer that prints on both sides) and have the CD-Rom as a back up. Does anyone know of who might do this for Pontiac? I need 69 Grand Prix.

I have a few photos of my GP SJ 4-speed at http://www.thecybermuseum.com/1969gpsj/ if anyone cares.

Dave

[69SJ4SPEED]

1) What is the CFM of the stock Quadrajet on the 69 428 in a Grand Prix?

2) The guy that sold me the car said that he had 66 heads put on it to lower the compression to burn 93 octane. They take AC's 44TS sparkplugs instead of the R45 that goes in the 428 heads that came on 69-74 428/455 heads. I'm learning Pontiac! What are these heads?

3) My fan to the A/C only has one speed. I wanted to change the Hi-blower relay (able to find) and blower resistor (can't find) as I'm told it is customary to change both at the same time. Anyone know where I can get one?

4) On my Dodge/Chryslers I've been able to buy Service / Parts / Body manuals on a CD-Rom for about $40 each from Detroit Iron. Their web site disappeared! I like these on CD-Rom as a can print the manual (I have a printer that prints on both sides) and have the CD-Rom as a back up. Does anyone know of who might do this for Pontiac? I need 69 Grand Prix.

I have a few photos of my GP SJ 4-speed at http://www.thecybermuseum.com/1969gpsj/ if anyone cares.

Dave

['ol Pinion head]

A '69 GP stick car will originally have a #7029263 Q-jet- 750 cfm... all pre '71 Q-jets were 750's. Nothing wrong with them, they are good carbs.

The casting #66 heads are standard on the '71 Bonneville-Grandville & SJ GP 455 mills & were used on the '71 455 D-port A-bodies. They have huge chambers (114 cc),press in studs, & have little marketable uses. They were available with both std & tapered seat plugs as late '71 model production was the changeover. Have seen one of each factory installed on the same engine...duhh.

With these heads & original style pistons in a 428, compression will be way down there. I imagine close to 7.0 to 1. I would consider going with either a set of correct dated 62's if originality is important or a set of 6x-4's.

Wish I could help you on the high speed blower question...someone will chime in. My '69 HO car has ATC, & I am buying up NOS & good used spare A/C parts as ATC parts for these are near extinct now. It will only be worse when I finally get it ready for the stockpiled R12.

[69SJ4SPEED]

Thanks for the reply.

I put on an exact replacement (identical)rebuilt carb on my GP today. I was just wondering what the CFM was.

The car runs pretty good with the new carb (they guy that sold me the car was running it without a fuel filter and the carb was trash) but it is a little slower that I expected. I thought it should be at least as fast as I remember my 68 GTO with a 400 4-speed. I'm thinking its the heads.

I don't care as much about the date coded stuff right now as I never have my cars judged. It has a replacement 428 with those 66 heads -- but the original block and heads on the shelf. The crank was trash so I left it with the seller. I intend to rebuild the original when I have a few less irons in the fire.

In the meantime is there an aftermarket head that works real well with this engine?

[Kurt Zimmerman]

Dave,
Nice car! There are very few Grand Prix that I like, but yours is one I could live with!!!
Very nice.

Kurt

------------------
" ...the monkeys were willing to strike up a tune." Jethro Tull

[GP-K]

Dave, I also have a '69 4 speed car. It is a 428 HO. Unfortunately, my original 428 HO 4 speed car was totaled in 1980 (frame bent ), so I transferred all of the parts to my current GP (bought shortly afterwards). The original car was a black/black SJ very much like yours. The one I have is red on black leather.

1) As far as the carb, I think that question has been pretty well answered.

2) The previous owner did you a real disservice by installing the large chamber heads on your car. Those heads are 1971 large valve 455 heads with, as OPH said 114 cc chambers, but I did think that they did have screw in studs - I could be wrong about that, but not about the cc's. As mentioned, with the #66 heads, you would have a compression ratio in the low 7:1 range.

That 428 would be a weak performer with the 067 cam and a compression ratio 3 full points lower than listed from the factory. Instead of the rated 370 hp (SAE Gross), you would be more in the 300 hp or less (SAE Gross) area. Consider that this would be about 220 net HP. Not much, considering 3900-4000 lbs to haul around.

The #62 heads, as well as 48's, 16's, and 12's (just to mention a few) would be a good (but a high compression, around 10:1, with a Fel-pro gasket) street head for that engine. With a little wilder cam, it might even tolerate the 93 octane gas. The factory 428 cast piston has a dish to allow the use of the same 72 cc heads as the 400's without having to increase chamber volume, or head gasket thickness. Once you have restored the compression ratio, you will be surprised in the improvement in power.

Edelbrock does make an aluminum head for Poncho's, as does Larry Wenzler. The Wenzler heads are a little more of a pure race head, but could be streetable. The E heads are available in 87 and 72 cc versions. Since all of these aftermarket heads are aluminum, they would be a little more compression forgiving than a cast iron head.

3) About the fan speed, the blower resistor is bolted into the outside passenger side front of the A/C condenser housing. If the blower will only run one speed, you could have a combination of a number of problems depending on which speed is working. These problems include the high blower relay, the in-line (from the alternator) 30 amp fuse, the blower resistor (less likely, but easy to check), and the ambient switch. The '69 shop manual will help here.

4) As far as Manuals, there are some available, both in reprint, and on CD-rom

Here is one source (for the '69 Fisher body manual on cd, to start)

Old n time cd shop manuals

Here is another

cd rom shop manuals

Hope this helps,
Enjoy.

K.

[mike nixon]

nice collection dave. the g/p is a sweet ride. mike

['ol Pinion head]

Dave,

The 72cc Edelbrock heads are THE option if you want (& need) the capabilities of aftermarket heads. The availablity of roundport headers to fit the GP chassis would be the problem. Or as GP-K, Mike, & I have mentioned before the nearly impossible to find RAII-RA4 bird roundport manifolds would really be the ticket... major dunero though! Easy to be out $2200-3400 this route-heads & exhaust.

If you just want to renew the stock (or better) performance level & run on pump gas, a set of 6X-4's milled .040 & treated to comp valve job, new guides, & decent springs should get the C/R back up to around 9.0 to 1. The 6x's flow a little better on the intake side than the original 16,62,48 heads. Without port work, you're looking at under $600 for a set of properly gone through milled 6x-4's including cores. If you have to have big valve exhausts, pop for new exhaust valves, lose the hardened seats, & cleanup the casting flash & short turn radius on the intake side to pick up a little more flow on the intake side.

Got to run, wife is dragging me off the computer to church... good luck on your GP...Roger

[69SJ4SPEED]

Roger--

I appreciate your help.

As I said in the earlier post -- I still have the (promised to be!) original heads to this engine. What casting were they suppose to be in 69, how can I verify that, and how good are they when rebuilt when compared to other Pontiac heads for a 428? If they do (or can be made to) perform well - what is the best recipe of springs, valves, seats, rockers,... to make them the best they can be for streetable -- but quick.

What was the stock compression of the 428 in a 69 GP?

[69SJ4SPEED]

GP-K

I missed your message at first glance. Thank you for the info. You guys are very responsive.

Nixon -- thanx for the Kudos.

[69SJ4SPEED]

GP-K

You might have something there on the fan. It is stuck on low. I have the relay and will replace it tomorrow and I want to find the resistor as it is cheap and accessible enough to eliminate as the problem -- but I have a fuseable link wire on the right side of the car (under the hood) that isn't attached to anything. I can't find where it goes.

Additionally, it is dead. I opened the fuse holder (no fuse in it) and put a test light to it (yes -- on what should have been the hot side). Dead. Do you think this might go to the A/C-Heater fan? If so what is the location each end should be at?