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Okay, I've built PLENTY of "hot" small blocks over the years. Now, I have a '73 'vette engine in for "restoration" and have some questions. Please answer if you KNOW the correct information.

Were '73s "tach-drive" iron distributors like the older ones? If not, what were they?

What would the correct casting number be for the cylinder head? I'm thinking "441", but can't recall and none of my books are that "specific".

The carb is a Q-Jet, 7043208. I know enough about Rochester numbers to know it's a '73, non-emmissions Chevy 4-bbl. The car has a manual trans. Is this the correct carb?

Thanks for any help.

Jim
 

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Evil Wicked Mean And Nasty
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Mr. P-Body said:
Okay, I've built PLENTY of "hot" small blocks over the years. Now, I have a '73 'vette engine in for "restoration" and have some questions. Please answer if you KNOW the correct information.

Were '73s "tach-drive" iron distributors like the older ones? If not, what were they?

What would the correct casting number be for the cylinder head? I'm thinking "441", but can't recall and none of my books are that "specific".

The carb is a Q-Jet, 7043208. I know enough about Rochester numbers to know it's a '73, non-emmissions Chevy 4-bbl. The car has a manual trans. Is this the correct carb?

Thanks for any help.

Jim
They were tach drive up to 74 i know for sure, i will have to check my books on the proper head casting numbers for you though. If i can find them. :embarrass



Cole
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Evil Wicked Mean And Nasty
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Here are all the # for 73.
in this order from left to right.
BLOCK/HEAD/INTAKE.EXAHUST LEFT/EXAHUST RIGHT. By the #s :thumbup:







350 - 190 HP L48 (early) 3970014 3998993 3997770 3932461 3932461
350 - 190 HP L48 (mid) 3970010 333881 3997771 3932461 3932461
350 - 190 HP L48 (late) 3970010 333882 3997771 3932461 3932461
350 - 250 HP L82 3970010 330545 3997771 3932461 3932461
454 - 275 HP LS4 3999289 353049 353015 3969869 3880828


Cole
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WFO
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Mr. P-Body said:
The carb is a Q-Jet, 7043208. I know enough about Rochester numbers to know it's a '73, non-emmissions Chevy 4-bbl. The car has a manual trans. Is this the correct carb?

Thanks for any help.

Jim
You will often hear that the last digit of the carb number correlates to the transmission type (even # = AT, odd = manual). But this is not always the case.

From the literature I have access to, carb number 7043208 is from a '73 Chevy truck/van (C, P, K 20 and 30 series) w/a SBC 350. No transmission type was specified, that means it could have been used on either an AT or manual equipped vehicle.

The -208 Q-jet came w/68 primary jets and 36 metering rods. The power piston spring is p/n 7037305 (7037305 is set for ~ 6 in/Hg, and would work well w/a high vacuum, smooth idling and/or wide LSA-type cam). Secondary metering rods are DA.

The only 'Vette w/SBC Q-jet listing I have is for:

Carb number 7043212 1973 'Vette Hi Perf. w/manual or AT: 74 jets; 44 rods; secondary rods DA; PP spring p/n 7036019 (has a tip in of about 8 in/Hg. For reference, GM part # 7029922 is a rather weak power piston spring that was OE for HO Pontiac engines from the early ‘70s. It delays enrichment until vacuum drops to ~3 in/Hg).

The "truck" carb you have will be somewhat lean during light throttle cruise conditions (6-8%). Where it is noticeably lean (18-20%) is under WOT/full enrichment (PP fully up).

You might be able to duplicate the rods and jets from the 'Vette specs into the truck carb, but there may be differences in the idle discharge hole diameter, diff. idle air bypass diameter, main and idle air bleed sizes, idle tube and channel restriction sizes, etc.

If it was me, I'd simply calibrate the carb internally giving it whatever it needed to allow the engine to run best, and not worry in the least what the stock calibrations were. GM and the rest of the industry were going through some bad times during that era w/emissions and economy; many engines- including Camaro/'Vette Hi Po engines- ran like crap from the factory anyway. Giving the advance curve a working over and setting up the carb right will wake it right up, even w/a stock cam.
 

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Too late to edit my last post...

It's worth noting that the carb you have- while showing up as a truck carb in the info I have- may be correct for the engine, depending on the RPO. I'm sure there are sites and/or literature available on that Corvette (probably the best documented domestic vehicle there is) that will say for sure one way or the other.

Good luck.
 
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