Intake gasket for Honda GX340, GX390 and big block clone engines.

Bullfrog Performance Products copper exhaust header gasket for Honda GX240, GX270, GX340, GX390, GX610, GX620 and GX690.  Will also fit Predator 420cc engines and many other big block clone engines.

Insulator with pulse fitting for Honda GX390 engines.

• Engineered to meet or exceed OE designs and withstand the extreme operating temperatures experienced during a powersports engine's combustion
• Iridium-enhanced 0.6mm finewire design for improved ignitability, faster fuel combustion and a more focused ignition versus standard plugs
• Up to 26 percent quicker starts compared to that of standard plugs and as much as 21 percent less hydrocarbon emissions than standard plugs, which promotes better fuel efficiency and horsepower

Copper head gasket available in a variety of bore and thickness ranges for the big block Honda GX390, 460cc, 500cc engines.  Select the gasket below that fits your build:

This head gasket fits Honda GX390 88mm bore and is .010" thick.

This head gasket is a graphite head gasket and will fit the Honda GX390 engine with 88mm bore.

Bullfrog Performance Products stainless steel intake valve fits Honda GX390, 460cc engines. We offer cylinder head machining to install larger valves into the Honda GX390 cylinder head. Select the valve head size you are looking for below. We highly recommend this valve when using high lift aftermarket racing cams to prevent valvetrain failure.
Be sure to include our billet aluminum or titanium valve spring retainer kit with our valve.

Gasket set for Honda GX390 engines.

Multi Layer Steel head gasket that fits the Honda GX390 engine.  Gasket has 89mm bore to fit the stock bore size on the Honda GX390.

Bullfrog Performance Products bronze valve guide set will fit the Honda GX340, GX390 and many other big block clone engines with factory diameter valve stem size of 6.5mm.  Our bronze valve guide will outperform in longevity and performance over the factory steel guide.  Has closer to the same heat expansion rate as aluminum head for a more stabil valvetrain operation.  These are sold as a pair of bronze guides.

Our Multi Layer Steel (MLS) head gasket fits the 460cc big block clone engines with 92mm bore size.

Our air filter adapter fits factory carburetor for Honda GX340 and GX390 engines. Also fits 420cc and 460cc engines with stock carburetor.
Be sure to order your air filter and pre-filter along with your air filter oil and cleaner.

Bullfrog Performance Products billet valve spring retainer kit fits Honda GX390 big block engines using our stainless steel or titanium valves.

A Shaft-Rocker eliminates the need for a guideplate and prevents the rocker arms from walking side-side. Furthermore, they have considerably more ridgidity than stud rockers.
These have a 1.1:1 Ratio and includes the studs and nuts to install the rockers in your engine.

Bullfrog Performance Products 65 lb. dual valve spring kit for the Honda GX390  big block single cylinder racing engines.  We highly recommend our 65 lb. kit when using any of our cams with .300" lift and higher.

Our custom ARP head bolt kit fits the Honda GX340, GX390, Predator 420cc, 460cc big block engines. Our ARP head bolt kit comes with the aircraft grade washers too. Maximize your head gasket clamp force with our ARP head bolt kit.

Gage Motorsports Black Venom roller rocker arm set fits Honda GX390 engine (non-hemi head).  This set is a 1.3 ratio.

Bullfrog Performance Products is the first in the industry to offer a 500cc big block racing engine package. We are always innovating and bringing new engine packages to the small engine performance enthusiast. Our 500cc longblock is custom built and comes with the following high quality components:

• Bullfrog Performance Products custom Big Bore tall deck cylinder block for stroker crank applications
• Bullfrog Performance Products custom forged piston and low drag ring kit
• Head Dowels
• Side Cover 10-Bolt
• ARP side cover bolt kit
• Solid side cover dowel pins
• Dipstick and oil fill cap
• Cranksaft oil seals made from Viton material for higher operating temperatures
• Roller main bearings
• Custom stroker crankshaft
• Bullfrog Performance Products billet connecting rod kit
• ARP rod bolts
• Babbit Rod Bearings
• Victor Reinz big bore fire ring style head gasket
• Bullfrog Performance Products custom head package
  • GX390 aftermarket cylinder head
  • Big valve package
  • Custom multi-angle valve job
  • Ported, polished and flow tested head
  • Dual valve spring package
  • Billet valve spring retainer kit
  • Chrome moly pushrod kit
  • Roller rocker arm package
  • ARP head bolt kit
  • Performance cam and lifter kit
  • Billet valve cover with integral cooling fins
  • Engine is a longblock