hood clearance w/ Bulldogs & SP-1

Hi folks,

Will be getting my Bulldog heads (which are taller than stock) back soon. Already sold my Performer intake. Now, I'm wondering if a made a mistake.

Was planning on using an SP-1 intake, which is also taller than stock/Edelbrock intakes. Does anyone know if I use a 2" K/N filter, with their open top, and a drop-base air cleaner, if I will have enough clearnace so as not to hit the hood? Definitely don't want a hood scoop.

Bought a drop-base air cleaner from Summit. Not sure if it's a 1" drop or a 2" drop base. Didn't know threre were two choices. Where do I get a 2" drop.

Was told by Jim Burek to use the SP-1, as using a dual-plane intake on Bulldog heads would be like putting a 2-barrel carb on it.

Thanks in advance.

Craig Stangohr
Aiken, SC

 

you need at least 3 inches of space between the carb and filter top. TA intakes need a 1" carb spacer to get the full benies. You have a hood problem without a doubt. You have a regal right? Our regal has issues with just a B4B.

 

David,

No Regal--a 1970 Skylark. John Osborn, who built my Q-jet, suggested a 1/2" non-open spacer (Barry Grant), to help w/ the low end, but I don't think I will have that luxury.

Thanks for your input.

I wonder how much taller the SP-1 intake is versus the Performer/B4B? Anybody know?

I might have to go back to the Performer, or B4B. Might be able to run a spacer then, even if it's only 1/2".

Any other input would be appreciated, before I have Gessler work on the SP-1 intake.

Hope everyone had a nice weekend/Father's day.

All the best,

Craig Stangohr
Aiken, SC.

 

Larry,

You may be correct in that Bulldogs would not affect the hood-clearance issue. Still, the Bulldogs are somewhat taller than the stock/TA heads, because one has to use a special spacer on the manifold ends--we can't simply use the stock end gaskets (or fill in w/ silicone).

Plenty of guys are running the SP-1 with their stock hoods, that's for sure, but I don't know if they have room for a spacer, though I suspect that some of them are using a spacer, with a drop-base air cleaner, even if it's only a 1/2" spacer.

Not do doubt David, but I wonder if 3" are really needed betweeen top of air filter and the hood? Any other opinions on that issue?

Thanks to all.

Regards,

Craig Stangohr
Aiken, SC

 

Larry,

sorry I misunderstood your original answer. 3" sounded a bit generous between the top of the air-cleaner lid and the inside of the hood!

Sounds like a 1"-drop air-cleaner base is about as much as one would want to go. Or, could one still run a 2" drop-air cleaner w/ a 3" element?

I will talk to Greg, but Jim Burek has stated that he has picked up almost 20 h.p. using the SP-1 versus the Edelbrock, using the Bulldog heads. However, this may be with a 600+ combo that see the north end of 6000 r.p.m.. I'm looking for 500-550 h.p. at about 5600 r.p.m.

I guess that explains why I don't see too many folks running a 2" air-filter element, even with the open K&N top.

Thanks, again.

Craig Stangohr
Aiken, SC

 

Larry,

Yes, I was looking for a bit crisper throttle response/low-end grunt. Think I'll return the SP-1 and get an Edelbrock. I guess it's a toss-up whether to go with the Permromer or B4B, as originality if not my concern. This issue has been debated on other threads.

Thanks, again.

regards,


Craig Stangohr
Aiken, SC

 

Ranger,

I have the same Bulldogs as you, but on my 71 GS. The heads caused the intake to sit marginally taller than with my 430 ones, because of the taller port design. Maybe .300"

I found by using an big block 70 Corvette drop base air cleaner I could get an extra inch of air cleaner height over some of the speed shop units. The vette design has a nice gentle radius and hugs the carb tightly. Remember GM engineered these with gentle curves to meet the flow demand of L-88's.

I used to run a 4" K&N, K&N filter lid, a T/A SP-1 all having clearnce with the stock hood.

As a side note , if you do run the Eddy intake, you could play around with machining the center divider to different heights, for added top end charge.
Tom

 

Tom,

thanks so much for the into. The big question is: where do I get this vette drop-based air cleaner?

Thanks Again,

Craig Stangohr
Aiken, SC

 

Craig, the intake will sit about .300 higher with the bulldog heads than with the stock heads. Jim Burek

 

Craig,

I found my at a swap meet. Look for any one of the late 60's early 70's chrome GM 360 deg OEM open air cleaners. They came on all Big inch Vettes, 396Camaros, Novas. Mine was actually off a Q-Jet 427 -390hp but the bases were formed to accept both Holley & Qjets. Just had to file off the neck alignment tab. Once I get my Camera up & running I'll post a pic.

Tom

 

Thank you Tom and Jim. I wonder if anyone is making repros of these air cleaners?

Jim, I bought the Bulldogs from you (through Greg Gessler). I assume that you are still favoring the SP-1 intake with these heads, even for a mild 500-525 h.p. combo?

Best Regards,

Craig Stangohr

 

Gm Air Cleaner

Craig,

Attached Pic of Bulldog headed motor with Sp-1 with no air cleaner

 

Gm Air Cleaner

With big Block Chebby Air cleaner base for more hood clearance. I've used 3 and 4 inch filter elements with this one. you should be safe with a 3" and have hood clearance.

Tom

 

Craig, I still feel a good single plane intake is the best compliment to those heads, but you should easily make your 525 horsepwoer even with something like the performer or b4b intake. By the way, do you have flow numbers on the heads yet? Jim Burek

 

Jim,

Thanks for your input. I am going to stick with the SP-1. Spoke w/ Greg the other day. He ordered my heads from you non-assembled, w/o the valve job, etc.

He said the intakes cleaned up pretty nicely with not a helluva lot more than a bowl blend--which the intakes definitely needed. He said there is a pretty sharp edge there right below the intake valve seat. He's not sure if Bullodg grinds that away when they sell the heads in "bolt-on" form. If they don't, he feels that would be a pretty sizeable restriction to flow.

He said the exhausts would need more work, for sure, than the intakes.

As I already knew, he warned me about comparing flow numbers from one flow bench to another--or from one dyno to another, for that matter. He has seen as much as a 10% difference in flow numbers from heads that were flowed by some reputable Buick head porters on their own flow bench, versus Greg's flow bench.

Still, he said that with not much more than a minor bowl blend, on HIS flow bench, the intakes were already flowing at about 220 c.f.m. I assume this was at .500 lift, though I did not verify it with him, as it might have been at .600 lift.

Still, he is in agreement with what you have previously stated, that the Bulldogs, at least on the intake ports, need less time/work to flow the same numbers when compared to the T/A SE heads.

Now, where can I find that Chevy drop-base air cleaner? I don't want to spend hours on E-Bay or at Swap meets. Doesn't anyone sell a repro? I would like to use a Barry Grant 1/2" spacer, even if I don't have room for a 1".

Best Regards and Thanks to all,


Craig Stangohr
Aiken, SC

 

Craig, I think you have a typo. You said 220 cfm on the intake, me thinks it would be much higher than that.
Drop base aircleaners are availalble at most any speed shop, even some of the auto parts chains carry them. Very common item and not very expensive. Jim Burek

 

Jim, sorry for correcting you, but hes reffering to the Chevy drop base used on more powerful chevy engines in 60's-70's. Its the same one that is pictured on the engine above. It has more of a drop than the drop-base filters you can find at shops and its more rounded, which should flow better.

Now im also wanting one of those drop-base filters, i think one of those with a 4" will flow better than a flat with a 2"

so ill search around, if i find any ill let you know!