Late Model Chevy Truck Heads (1998) on a 1981 305 block?

[TURNA]

Late Model Chevy Truck Heads (1998) on a 1981 305 block?

I saw a recent Car Fix Episode where they put heads off a 1998 Chevy truck on one of our 305 motors mine is in an 81 Monte. They put a cam in a performer intake manifold on and topped it with a Holley 600 CFM Carb and claim 300 Horse Power. Anyone have experience and success with such a...

gbodyforum.com

 

[TURNA]

Late model 305 Chevy Truck heads on one of our 305? (mine is an 81 Monte)

I heard heads from a late model 305 in this case from a 1998 Chevy truck will fit on one of our blocks. And if you upgrade Cam, Intake and Carb you will flow enough to get 300 horse power. I would like to get 300 HP out of my 81 Monte on a budget. Anyone have details on this working or am I...

gbodyforum.com

 

[gnvair]

I have a local engine core supplier that I have been buying rebuilable engines from for years. He will no longer sell 906/062 Vortecs because they are almost always cracked. Either buy new GM or look into the Engine Quest replacements.
One other detail is that 305s typically have small combustion Chambers to keep the compression up. The 906/062 Vortecs have a larger chamber. Putting them on a 305 will lower the compression.

 

[olds307 and 403]

I have a local engine core supplier that I have been buying rebuilable engines from for years. He will no longer sell 906/062 Vortecs because they are almost always cracked. Either buy new GM or look into the Engine Quest replacements.
One other detail is that 305s typically have small combustion Chambers to keep the compression up. The 906/062 Vortecs have a larger chamber. Putting them on a 305 will lower the compression.

Exactly my point, lower compression. Without out a converter and gear change, 305 Vortec heads might be better. I was told the same thing from a wrecker about Dodge Magnum heads, they would not sell them even if they had them because of cracks. So I bought the Ram EQ heads. Hopefully the EQ Vortec heads don't have sticking valves like the EQ Magnum heads. I bought the Hughes modified EQ heads with bronze guides, 0 issues.

 

[Streetbu]

I am surprised they even bothered with different heads. I assume smaller valves and ports? I know the 5L Vortec were rated at 230 HP, got mid to high 20's mpg Imperial and only made a couple of years.

Honestly not sure about port sizes, the valves are the same, but the chamber is like an older 882 head, bathtub design. Not like the actual good Vortec head that flows so well.

 

[Jeff]

Thanks everyone. New here and started two threads without realizing sorry. All good information and lots to consider. I am leaning to not doing an engine swap even though I know a 350 would be a better option. The 305 in the car is fresh well about 25K on a rebuild (verified) the person I bought if from had done at a reputable machine shop. I called that shop and they will hook me up with the right 350 Vortec Heads in good shape for $300. I figure a cam $125 and the shop will sell me a performer intake they have for $75. My sons friends Dad is giving me a 615 CFM Predator he does not use. Headers $150 or so. My kid who is getting this car for his 16th birthday will definitely be surprised. He and I have spent allot of time getting the brakes, steering components all bushings etc. shocks up to par. He thinks its my car. I got until September to finish the engine mods. I think this will be enough power for a young-in anyway.

 

[Gremlinsteve]

Those seem to be good prices if you ask me

 

[RabbitHoleSS]

Thanks everyone. New here and started two threads without realizing sorry. All good information and lots to consider. I am leaning to not doing an engine swap even though I know a 350 would be a better option. The 305 in the car is fresh well about 25K on a rebuild (verified) the person I bought if from had done at a reputable machine shop. I called that shop and they will hook me up with the right 350 Vortec Heads in good shape for $300. I figure a cam $125 and the shop will sell me a performer intake they have for $75. My sons friends Dad is giving me a 615 CFM Predator he does not use. Headers $150 or so. My kid who is getting this car for his 16th birthday will definitely be surprised. He and I have spent allot of time getting the brakes, steering components all bushings etc. shocks up to par. He thinks its my car. I got until September to finish the engine mods. I think this will be enough power for a young-in anyway.

He hasn't asked if its gonna be his? My boys only 7 and is staking claim to my monte lol. That's an awesome 16th bday present. To get the car you and your old man fixed up. I wish my dad woulda done stuff like this with me. Nothing better then bringing joy to your kids imo. Mine isn't a teenager yet so well see how I feel in another 7 yrs.

 

[melloelky]

make sure you check the hood clearance with that Predator,they're a little tall.

 

[Clone TIE Pilot]

Make sure they are Vortec heads off a 350 and not off a Vortec 305. Completely different heads. The 305 heads don't give nearly the performance gain.

350 Vortec heads would cause a severe compression drop besides the valves being too large and would be shrouded. Vortec 305 heads, the 059 castings would be the better choice for 305s, and they are the second highest flowing factory SBC heads. Plenty of F body guys pump out 300 HP out of their 305s using 059 Vortec heads and CCC Qjets.Witb either Vortec heas the OP will need a Vortec intake. Skip the aftermarket carbs, they are a waste of money, the CCC Qjet is good to 400 Hp.