Hi Guys
Curious about something,
I know where I can get a very original 85 Iroc (5-spd),I think it has the 305 HO Carb engine.Would swapping to a built up 350 make sense as far as detracting from value,desirabilty etc?
I assume other changes would have to be made to do the swap.
is this something anyone has done,or considered doing?
Thanks

 

Another comment,
I get the idea that TPI cars are more desirable than the carb cars?
Any truth to that?
Thanks

 

With the exception of a couple rare cars TTA, 1LE and some others matching numbers dont mean much for the car. If you like it and it is clean then swap a 350 if you want to. Also Yes EFI will generally be worth more than carb and TPI is worth more than TBI

 

Get you a 350 and you wont be sorry. Wont hurt the value either. They look identical but definitely wont be.

 

Thanks Guys
How much HP will a T5 handle ?

 

IMO, I would take a 305HO over a TPI car.

 

Depends on who you talk to..
The factory rated the non-WC (earlier) T-5 at something like 275 ft lb of torque if memory serves. (I could be wrong, but it's low like that) The WC (later) was rated something like 300 ft lb.
Some people say they sneezed while driving and that's what broke the trans....others like me have one living happily behind a warmed up 350. Two sides of a coin.
I personally have a 400 ft lb 350ci motor turning a WC T-5 and it's fine. I have a good shifter and I don't burn the tires off.
A good T-56 is a much better idea but depending on power and driving habits, a T-5 will work.

 

Thanks Guys,
Well the car I have now purchased is a 1986 Iroc wth an LG4 engine.code H according to vin (T5 trans)
Problem is that it has a 305HO emblem on the left rear bumper,so Im assuming it was stuck on by previous owner.
Its a carbed car,so any suggestions on the easiest 350 swap candidates i would appreciate.
By reading through these forums I see the L31 looks like a good low stress option
Thanks
Shawn

 

L31 should bolt right in you just need a vortec manifold and you can keep the carb if you want

 

In your situation, I'd personally go with a crate vortec 350 from gm and change to a mild cam and a real exhaust. There are limits to the size of cam using stock vortec springs and such so pay mind to that if you go that route. Being a carbed car, the only thing would be mechanical fuel pump provisions. Other wise it's straight forward.

 

Jegs had L31-Rs yesterday for $1599 with $100 off coupon to boot!

 

Got a LINK? I can't find it on jegs.com at any price.

 

https://www.jegs.com/i/JEGS/059/0282/10002/-1

 

Thanks midias!

 

Hi Folks
Me again,
I found a nice built 350 engine,a 1969 block though.
My question is,will it bolt up to the T5 ok?
Thanks
Shawn

 

Pass on any block from before 1987. This is roller cam country, we don't be takin too kindly to those oil leakin flatted lobe garbage blocks from the dark ages.

In all seriousness, there's absolutely no reason to mess with OLD small blocks. 87-up blocks will fit better all around.

 

Yes. Bellhousing bolt pattern is the same.

 

Bolting to the bellhousing is the least of worries. The car is an 86, one piece rear main seal. That means 1pc rear mainseal crank. If you want the existing flywheel to bolt up, you want an 86 or newer block. Beyond that, you don't want to go from a 1pc to a 2pc rms if you can help it. 2pc rear main seals leak. The multipiece oil pan gasket, leaks. The dipstick location won't work without headers. The starter probably won't bolt up. Who knows what other provisions an older block won't have? Then you've got the flat tappet cam that even the car mags can't seem to make survive with modern oils.

Forget all that crap, get a Vortec 350 block and deal with the problems that come with UPGRADING instead of downgrading.

 

I agree! If I did not live in a communist state, I'd have an L98R w/ 350 injectors, prom, SD ( Sgonin Dicky, or something like that, I forget) lower intake.

 

Well put!

 

Hi Folks ,I am back again,
Thanks for the info.
So just to be clear,I can pull my 305 non CC carbed engine(Canadian ),get a 96-2000 Vortec used,or buy a new L31.
Then,get a vortec manifold for my Quadrajet,and reinstall with all my existing brackets,distributor etc.
No clearance or height issues?
Thanks Shawn

 

depends on which manifold you purchase. Go to Summit Racing. Look up a carb intake for vortec engine. Then refine results down to spread bore (Qjet) mounting and there are 10 results ranging from 4.25in to 6.060in height.
How much taller is that from stock? I don't know with out measuring. You could probably do that with your own.

See intakes here...if my link works

 

Thanks,I will check it out.
What kind of fuel delivery systems did these engines have?
TBI,TPI, etc.
Do I need to worry about plugging holes in the heads,etc,fuel runners etc.
Shawn

 

From my experience the aftermarket Vortec intake manifolds, they will be a good bit taller than the original Q-jet intake on the 305 HO. Look into a drop base air cleaner to avoid any hood clearance issues.

The Vortec engine is essentially the best modern version of the SBC. Even though the cylinder wall casting are no where near as thick as the older 70’s blocks. Core shift is always an issue too on these blocks too.

*Note there is not mechanical fuel pump provision on the Vortec block. At least not on the Vortec 350’s that I have from a 98 Suburban and Silverado. The push rod hole is not cast into the block. You will have to add an electric fuel pump like a Holley blue or red pump.

As far as the original injection system on the Vortec engines. It’s an two piece manifold with and aluminum base and a plastic top. The injection system is strange kind of like spider legs with tubes running everywhere.

One last note if you buy a used L31 it might be wise to check the cam bearings depending on the mileage. The few I’ve taken apart I could see the cam bearings were worn into the copper. Last one I took a part had 85,000 on it for reference.
Look at a new one if possible.

 

Thank you!