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Crate Engine upgrades - what are the right ones to do?

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boboftherockies

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Discussion starter · #1 ·
I'm planning to pull the engine and trans out of my 69 to do a tranny swap to a 700r4 and while I've got the engine out I want to do an upgrade to gain some HP and Torque. The engine is a GM crate 350 HO with 330 HP / 380 FT/lbs torque with FAST EZ EFI and the following specs:

Camshaft duration (@.050 in): 212 degree intake / 222 degree exhaust
Camshaft lift (in):.435 intake / .460 exhaust
Hydraulic flat tappet
Compression ratio: 9.1:1
Cylinder head Type: Vortec iron; 64 cc chambers
Valve size (in): 1.94 intake / 1.50 exhaust

I don't want to touch the bottom end, but I'd like to try to get into the 400+ HP range with just valve train changes - simpler is better. I don't want a beast... it needs to be good to drive daily (not a big lumpy idle and decent fuel mileage). I'm also in the Denver area, so I loose some power up here.

The questions I have are:
1) Will a head upgrade to aluminum with bigger valves / better flow #'s make a big difference on their own (without a cam change too)? Or, should I stick with the iron Vortec's?
2) do I need to do a cam upgrade with heads or can I just do heads and get what I'm looking for? If so, should I do a roller cam with roller rockers? Can I just do roller rockers without a cam change if I do just the heads?
3) I'm comfortable doing a head change, but have not done a cam install before, is it straightforward (timeing set, degreeing, etc)?
4) Of the big name head / valve train makers - which ones make the best stuff at the best price (Eddy, Trick Flow, Comp, AFR, etc)

Cost is a factor but not if it means cutting corners.

Thanks for your ideas!
Bob
 
#2 ·
I wouldn't spend any money on new heads. Keep those vortec heads they are very good heads. Have a shop go through them to make sure everything is good. Have the shop do the modifications so that you can get more lift. Change the cam to something bigger. Get the appropriate valve springs for whatever cam you choose.

You will have a big smile on your face when you drive it again.
 
#3 ·
If you don't want to touch the dished piston 9:1 short block then it's going to be the limiting factor. If you want to keep your intake and valve covers you're limited to Vortec style heads.

There is a Vortec head dyno comparison Chevy High Performance and the best head they tested was the Edelbrock E-Tec which only picked up 17hp peak compared to a stock Vortec head (408 vs 391) and that was on a 10:1 roller cammed 355. This was before the AFR Vortec head came out so I don't know how it would compare or what others are out there now.
http://www.chevyhiperformance.com/techarticles/148_0507_street_style_vortec_head_test/index.html

Here's the thing..... Vortecs are a very good torque and hp street head but they are not an absolutely ideal hp head. Just as an example, Chevy High Performance did a budget Vortec head 406 a while back: 9.5 compression, 230 single pattern cam, and Vortec 64cc heads. They changed out only the heads to a 68cc AFR non-Vortec head (resulted in a small drop in compression) and picked up 49hp.

I'd guess a 70hp bump with your guidelines of "I don't want a beast... it needs to be good to drive daily (not a big lumpy idle and decent fuel mileage)." would take at least something like a set of those Pro-Filer heads worked by Chad Speier or some AFR-180 heads, new intake, new valve train, and more cam. You're probably looking at around $1600-$2000 in parts there.

It's not too hard to get 400hp out of a 350 but handicapping it with low compression doesn't help. Take this 9:1 350 with a grain of salt.
http://www.airflowresearch.com/chevy_dyno.php
 
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Discussion starter · #4 ·
Steiner said:
If you don't want to touch the dished piston 9:1 short block then it's going to be the limiting factor. If you want to keep your intake and valve covers you're limited to Vortec style heads.

There is a Vortec head dyno comparison Chevy High Performance and the best head they tested was the Edelbrock E-Tec which only picked up 17hp peak compared to a stock Vortec head (408 vs 391) and that was on a 10:1 roller cammed 355. This was before the AFR Vortec head came out so I don't know how it would compare or what others are out there now.
http://www.chevyhiperformance.com/techarticles/148_0507_street_style_vortec_head_test/index.html

Here's the thing..... Vortecs are a very good torque and hp street head but they are not an absolutely ideal hp head. Just as an example, Chevy High Performance did a budget Vortec head 406 a while back: 9.5 compression, 230 single pattern cam, and Vortec 64cc heads. They changed out only the heads to a 68cc AFR non-Vortec head (resulted in a small drop in compression) and picked up 49hp.

I'd guess a 70hp bump with your guidelines of "I don't want a beast... it needs to be good to drive daily (not a big lumpy idle and decent fuel mileage)." would take at least something like a set of those Pro-Filer heads worked by Chad Speier or some AFR-180 heads, new intake, new valve train, and more cam. You're probably looking at around $1600-$2000 in parts there.

It's not too hard to get 400hp out of a 350 but handicapping it with low compression doesn't help. Take this 9:1 350 with a grain of salt.
http://www.airflowresearch.com/chevy_dyno.php
Click to expand...
Good stuff Steiner - as usual.
The car is nice to drive as it is and the tranny change to a 700r4 with 3.55 gears (it's an 8.5 10 bolt) will certainly make it a lot better than the TH350 with 3.08s. $2000 seems like a lot to put into the existing engine to get new heads that will still be limited by the 9:1 compression. I think I'll keep what I have until I feel the need to do the bottom end too.

Bob
 
#5 ·
Your cam is pretty small - a roller cam with more lift and duration could get you another 50 hp and more torque, but you can't go too wild with the low compression. Probably $1300 going that route which would include, cover with button, pushrods, cam, lifters, cam gear with torrington bearing and rockers. Setting the cam end play and then picking the right pushrods (length required depends on several factors) would be the more technical part of the installation - you can also degree the cam (desirable).
 
#6 ·
I feel for you, man. I was on a project in Denver for nine months and had my supercharged truck and a couple of motorcycles with me. That altitude almost killed me when I first got out there and did a number on my rides. I think you take around a 25% hp hit just in Denver without hitting the mountains.

The good thing about the 700R4 and 3.55 is that first gear will soak up a healthy cam if you decide to do that.
 
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Discussion starter · #7 ·
Steiner said:
I feel for you, man. I was on a project in Denver for nine months and had my supercharged truck and a couple of motorcycles with me. That altitude almost killed me when I first got out there and did a number on my rides. I think you take around a 25% hp hit just in Denver without hitting the mountains.

It's all relative.... everyone else up here has to live with the drop in power too:D

It's also why I went to EFI.... manages the altitude issues great!

Thanks
Bob
Click to expand...
 
Discussion starter · #8 ·
srode said:
Your cam is pretty small - a roller cam with more lift and duration could get you another 50 hp and more torque, but you can't go too wild with the low compression. Probably $1300 going that route which would include, cover with button, pushrods, cam, lifters, cam gear with torrington bearing and rockers. Setting the cam end play and then picking the right pushrods (length required depends on several factors) would be the more technical part of the installation - you can also degree the cam (desirable).
Click to expand...
.... if I go that route, I still need to get the Vortec heads worked to allow for a larger lift. Stock Vortecs are really limited on lift.

Thanks
Bob
 
#10 ·
#11 ·
I've had the 350/33ho in my 69z for 8 years now. I installed a lunati voodoo cam and crane 10309 springs that fix perfectly without machining. It makes around 375 to 385hp and runs great. If i had to do all over again i would have probably just gone with the GMPP hotcam kit and have the heads machined for the springs that come with the kit should make a solid 385 to 400hp with reliable gm parts. The block is roller ready now youjust need the kit, timing chain spider assembly and cam retainer plate.
 
Discussion starter · #12 ·
BPOS said:
Do your own research, but I'm pretty sure the 350HO is a factory roller block, which would be sweet. Somewhere (I can't find it) I remember reading one of the mags installed the GMPP Hot Cam and an RPM Airgap Vortec and made just over 400 HP with it. You'd need to have the heads worked for the added lift still.

Edit - here it is. http://www.carcraft.com/projectbuil...ld/116_0403_350_ho_crate_engine_hydraulic_roller_cam_package_install/index.html
Click to expand...
Great article BPOS! Thanks....
Bob
 
Discussion starter · #13 ·
Dave69Z said:
I've had the 350/33ho in my 69z for 8 years now. I installed a lunati voodoo cam and crane 10309 springs that fix perfectly without machining. It makes around 375 to 385hp and runs great. If i had to do all over again i would have probably just gone with the GMPP hotcam kit and have the heads machined for the springs that come with the kit should make a solid 385 to 400hp with reliable gm parts. The block is roller ready now youjust need the kit, timing chain spider assembly and cam retainer plate.
Click to expand...
Thanks Dave!
 
Discussion starter · #14 ·
After doing a lot of reading and research, it seems that the vortec heads are pretty good in stock form but their big limitation is the < .475 lift and their flow on the exhaust side. Making the vortecs work with >.500 lift roller cam with roller rockers means machine work to handle the lift, new springs (or use conicals), add screw in 3/8 studs, etc. The cost of this work ($1000-ish) may be enough to outweigh the cost of new heads....

New questions:
1) Can I safely increase compression to 9:7 or so with my existing dished pistons (9:1 compression with the 64cc chambers on the vortec's) by going to a head with somewhere between 2 and 8cc less volume in the combustion chamber (62cc - 56cc)? AFR 190cc vortecs offer flat milling options.
2) If if can do #1, will the valves still clear if I keep the lift to <.520? I know I'd need to check the clearance once all the parts are ready to get put together, but I'd like to hear if anyone has done this and seen issues with valve clearance?

Thanks!
Bob
 
#15 ·
boboftherockies said:
I'm planning to pull the engine and trans out of my 69 to do a tranny swap to a 700r4 and while I've got the engine out I want to do an upgrade to gain some HP and Torque. The engine is a GM crate 350 HO with 330 HP / 380 FT/lbs torque with FAST EZ EFI and the following specs:

Camshaft duration (@.050 in): 212 degree intake / 222 degree exhaust
Camshaft lift (in):.435 intake / .460 exhaust
Hydraulic flat tappet
Compression ratio: 9.1:1
Cylinder head Type: Vortec iron; 64 cc chambers
Valve size (in): 1.94 intake / 1.50 exhaust

I don't want to touch the bottom end, but I'd like to try to get into the 400+ HP range with just valve train changes - simpler is better. I don't want a beast... it needs to be good to drive daily (not a big lumpy idle and decent fuel mileage). I'm also in the Denver area, so I loose some power up here.

The questions I have are:
1) Will a head upgrade to aluminum with bigger valves / better flow #'s make a big difference on their own (without a cam change too)? Or, should I stick with the iron Vortec's?
2) do I need to do a cam upgrade with heads or can I just do heads and get what I'm looking for? If so, should I do a roller cam with roller rockers? Can I just do roller rockers without a cam change if I do just the heads?
3) I'm comfortable doing a head change, but have not done a cam install before, is it straightforward (timeing set, degreeing, etc)?
4) Of the big name head / valve train makers - which ones make the best stuff at the best price (Eddy, Trick Flow, Comp, AFR, etc)

Cost is a factor but not if it means cutting corners.

Thanks for your ideas!
Bob
Click to expand...
Ok, 400 HP is going to give you 300 HP in denver, the next problem is your going to have 300 TQ, now by the time the 700R4 blows through low gear with very little TQ multiplication, the pictures bleak at best. You need compression, and in a bad way. The vortec heads correctley worked would be a good package, but they dont lend themselves to massive milling to raise the compression. So this what I would do in your position, your going to have go into the shortblock to make it run, that just a fact, I world use a .100 domed speedpro hyp piston, I would mill a slot in the dome to clear the spark plug pad, I would lighten the pistons to the factory GM pistons, decking the block to 9.000 wound'nt hurt either. I would find a shop that can work the heads properly. Cam would be a 225@.050, .500 lift HYD roller, performer RPM intake. Now if this was done by the right people you could have 440 HP and 450 TQ, and it shouldnt cost a fortune. I would stick with the 3.08 gear and buy a real converter for the turbo, but thats just me.
 
#17 ·
Put in a procharger.
 

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#18 ·
If you are going to have any head work done (or even if you aren't cheap insurance) make sure to have a machine shop check to make sure the head surface is flat and straight as well as checking the valve seats and guides.

I did lot of work on my brand new Brodix heads to bring them into acceptable tolerances/runout. I had 0.009" runout on the valve seats when really you want less than 0.001". I guess most cylinder head manufacturers want you to pay for there CNC or custom head work jobbers to actually get good tolerances. This wasn't the only time I saw that, every brand new cylinder head (Dart, AFR etc) we looked at had similar issues as well. But I'm picky and was able to do this work myself in my engine machining class.

It will make a major difference on a daily driver how well it runs and how much HP/tq it makes if the valves actually seal well and can hold 20" of vacuum.
 
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